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. */ 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