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npf_alg.c revision 1.5 
      1 /*	$NetBSD: npf_alg.c,v 1.5 2012/07/15 00:23:00 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 1.5 2012/07/15 00:23:00 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. */
     50 struct npf_alg {
     51 	LIST_ENTRY(npf_alg)		na_entry;
     52 	npf_alg_t *			na_bptr;
     53 	npf_algfunc_t			na_match_func;
     54 	npf_algfunc_t			na_out_func;
     55 	npf_algfunc_t			na_in_func;
     56 	npf_algfunc_t			na_seid_func;
     57 };
     58 
     59 static LIST_HEAD(, npf_alg)		nat_alg_list	__cacheline_aligned;
     60 static kmutex_t				nat_alg_lock	__cacheline_aligned;
     61 static pserialize_t			nat_alg_psz	__cacheline_aligned;
     62 
     63 void
     64 npf_alg_sysinit(void)
     65 {
     66 
     67 	mutex_init(&nat_alg_lock, MUTEX_DEFAULT, IPL_NONE);
     68 	nat_alg_psz = pserialize_create();
     69 	LIST_INIT(&nat_alg_list);
     70 }
     71 
     72 void
     73 npf_alg_sysfini(void)
     74 {
     75 
     76 	KASSERT(LIST_EMPTY(&nat_alg_list));
     77 	pserialize_destroy(nat_alg_psz);
     78 	mutex_destroy(&nat_alg_lock);
     79 }
     80 
     81 /*
     82  * npf_alg_register: register application-level gateway.
     83  *
     84  * XXX: Protected by module lock, but unify serialisation later.
     85  */
     86 npf_alg_t *
     87 npf_alg_register(npf_algfunc_t match, npf_algfunc_t out, npf_algfunc_t in,
     88     npf_algfunc_t seid)
     89 {
     90 	npf_alg_t *alg;
     91 
     92 	alg = kmem_zalloc(sizeof(npf_alg_t), KM_SLEEP);
     93 	alg->na_bptr = alg;
     94 	alg->na_match_func = match;
     95 	alg->na_out_func = out;
     96 	alg->na_in_func = in;
     97 	alg->na_seid_func = seid;
     98 
     99 	mutex_enter(&nat_alg_lock);
    100 	LIST_INSERT_HEAD(&nat_alg_list, alg, na_entry);
    101 	mutex_exit(&nat_alg_lock);
    102 
    103 	return alg;
    104 }
    105 
    106 /*
    107  * npf_alg_unregister: unregister application-level gateway.
    108  */
    109 int
    110 npf_alg_unregister(npf_alg_t *alg)
    111 {
    112 
    113 	mutex_enter(&nat_alg_lock);
    114 	LIST_REMOVE(alg, na_entry);
    115 	pserialize_perform(nat_alg_psz);
    116 	mutex_exit(&nat_alg_lock);
    117 
    118 	npf_core_enter();
    119 	npf_ruleset_freealg(npf_core_natset(), alg);
    120 	npf_core_exit();
    121 
    122 	kmem_free(alg, sizeof(npf_alg_t));
    123 	return 0;
    124 }
    125 
    126 /*
    127  * npf_alg_match: call ALG matching inspectors, determine if any ALG matches.
    128  */
    129 bool
    130 npf_alg_match(npf_cache_t *npc, nbuf_t *nbuf, npf_nat_t *nt)
    131 {
    132 	npf_alg_t *alg;
    133 	bool match = false;
    134 	int s;
    135 
    136 	s = pserialize_read_enter();
    137 	LIST_FOREACH(alg, &nat_alg_list, na_entry) {
    138 		npf_algfunc_t func = alg->na_match_func;
    139 
    140 		if (func && func(npc, nbuf, nt)) {
    141 			match = true;
    142 			break;
    143 		}
    144 	}
    145 	pserialize_read_exit(s);
    146 	return match;
    147 }
    148 
    149 /*
    150  * npf_alg_exec: execute ALG hooks for translation.
    151  */
    152 void
    153 npf_alg_exec(npf_cache_t *npc, nbuf_t *nbuf, npf_nat_t *nt, const int di)
    154 {
    155 	npf_alg_t *alg;
    156 	int s;
    157 
    158 	s = pserialize_read_enter();
    159 	LIST_FOREACH(alg, &nat_alg_list, na_entry) {
    160 		if ((di & PFIL_OUT) != 0 && alg->na_out_func != NULL) {
    161 			(alg->na_out_func)(npc, nbuf, nt);
    162 			continue;
    163 		}
    164 		if ((di & PFIL_IN) != 0 && alg->na_in_func != NULL) {
    165 			(alg->na_in_func)(npc, nbuf, nt);
    166 			continue;
    167 		}
    168 	}
    169 	pserialize_read_exit(s);
    170 }
    171 
    172 bool
    173 npf_alg_sessionid(npf_cache_t *npc, nbuf_t *nbuf, npf_cache_t *key)
    174 {
    175 	npf_alg_t *alg;
    176 	bool nkey = false;
    177 	int s;
    178 
    179 	s = pserialize_read_enter();
    180 	LIST_FOREACH(alg, &nat_alg_list, na_entry) {
    181 		npf_algfunc_t func = alg->na_seid_func;
    182 
    183 		if (func && func(npc, nbuf, (npf_nat_t *)key)) {
    184 			nkey = true;
    185 			break;
    186 		}
    187 	}
    188 	pserialize_read_exit(s);
    189 	return nkey;
    190 }
    191