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npf_alg.c revision 1.2.10.1 
      1 /*	$NetBSD: npf_alg.c,v 1.2.10.1 2012/04/17 00:08:38 yamt 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 1.2.10.1 2012/04/17 00:08:38 yamt 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. */
     49 struct 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 
     58 static LIST_HEAD(, npf_alg)		nat_alg_list	__read_mostly;
     59 
     60 void
     61 npf_alg_sysinit(void)
     62 {
     63 
     64 	LIST_INIT(&nat_alg_list);
     65 }
     66 
     67 void
     68 npf_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  */
     79 npf_alg_t *
     80 npf_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  */
     98 int
     99 npf_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  */
    118 bool
    119 npf_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  */
    136 void
    137 npf_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 
    153 bool
    154 npf_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