npf_state.c revision 1.10
1 /* $NetBSD: npf_state.c,v 1.10 2012/07/21 17:11:01 rmind Exp $ */ 2 3 /*- 4 * Copyright (c) 2010-2012 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 state engine to track sessions. 34 */ 35 36 #include <sys/cdefs.h> 37 __KERNEL_RCSID(0, "$NetBSD: npf_state.c,v 1.10 2012/07/21 17:11:01 rmind Exp $"); 38 39 #include <sys/param.h> 40 #include <sys/systm.h> 41 42 #include <sys/mutex.h> 43 44 #include "npf_impl.h" 45 46 /* 47 * Generic session states and timeout table. 48 * 49 * Note: used for connnection-less protocols. 50 */ 51 52 #define NPF_ANY_SESSION_CLOSED 0 53 #define NPF_ANY_SESSION_NEW 1 54 #define NPF_ANY_SESSION_ESTABLISHED 2 55 #define NPF_ANY_SESSION_NSTATES 3 56 57 static const int npf_generic_fsm[NPF_ANY_SESSION_NSTATES][2] = { 58 [NPF_ANY_SESSION_CLOSED] = { 59 [NPF_FLOW_FORW] = NPF_ANY_SESSION_NEW, 60 }, 61 [NPF_ANY_SESSION_NEW] = { 62 [NPF_FLOW_FORW] = NPF_ANY_SESSION_NEW, 63 [NPF_FLOW_BACK] = NPF_ANY_SESSION_ESTABLISHED, 64 }, 65 [NPF_ANY_SESSION_ESTABLISHED] = { 66 [NPF_FLOW_FORW] = NPF_ANY_SESSION_ESTABLISHED, 67 [NPF_FLOW_BACK] = NPF_ANY_SESSION_ESTABLISHED, 68 }, 69 }; 70 71 static u_int npf_generic_timeout[] __read_mostly = { 72 [NPF_ANY_SESSION_CLOSED] = 0, 73 [NPF_ANY_SESSION_NEW] = 30, 74 [NPF_ANY_SESSION_ESTABLISHED] = 60, 75 }; 76 77 /* 78 * npf_state_init: initialise the state structure. 79 * 80 * Should normally be called on a first packet, which also determines the 81 * direction in a case of connection-orientated protocol. Returns true on 82 * success and false otherwise (e.g. if protocol is not supported). 83 */ 84 bool 85 npf_state_init(const npf_cache_t *npc, nbuf_t *nbuf, npf_state_t *nst) 86 { 87 const int proto = npf_cache_ipproto(npc); 88 bool ret; 89 90 KASSERT(npf_iscached(npc, NPC_IP46)); 91 KASSERT(npf_iscached(npc, NPC_LAYER4)); 92 93 memset(nst, 0, sizeof(npf_state_t)); 94 mutex_init(&nst->nst_lock, MUTEX_DEFAULT, IPL_SOFTNET); 95 96 switch (proto) { 97 case IPPROTO_TCP: 98 /* Pass to TCP state tracking engine. */ 99 ret = npf_state_tcp(npc, nbuf, nst, NPF_FLOW_FORW); 100 break; 101 case IPPROTO_UDP: 102 case IPPROTO_ICMP: 103 /* Generic. */ 104 nst->nst_state = npf_generic_fsm[nst->nst_state][NPF_FLOW_FORW]; 105 ret = true; 106 break; 107 default: 108 ret = false; 109 } 110 NPF_TCP_STATE_SAMPLE(nst, ret); 111 return ret; 112 } 113 114 void 115 npf_state_destroy(npf_state_t *nst) 116 { 117 118 nst->nst_state = 0; 119 mutex_destroy(&nst->nst_lock); 120 } 121 122 /* 123 * npf_state_inspect: inspect the packet according to the protocol state. 124 * 125 * Return true if packet is considered to match the state (e.g. for TCP, 126 * the packet belongs to the tracked connection) and false otherwise. 127 */ 128 bool 129 npf_state_inspect(const npf_cache_t *npc, nbuf_t *nbuf, 130 npf_state_t *nst, const bool forw) 131 { 132 const int proto = npf_cache_ipproto(npc); 133 const int di = forw ? NPF_FLOW_FORW : NPF_FLOW_BACK; 134 bool ret; 135 136 mutex_enter(&nst->nst_lock); 137 switch (proto) { 138 case IPPROTO_TCP: 139 /* Pass to TCP state tracking engine. */ 140 ret = npf_state_tcp(npc, nbuf, nst, di); 141 break; 142 case IPPROTO_UDP: 143 case IPPROTO_ICMP: 144 /* Generic. */ 145 nst->nst_state = npf_generic_fsm[nst->nst_state][di]; 146 ret = true; 147 break; 148 default: 149 ret = false; 150 } 151 NPF_TCP_STATE_SAMPLE(nst, ret); 152 mutex_exit(&nst->nst_lock); 153 154 return ret; 155 } 156 157 /* 158 * npf_state_etime: return session expiration time according to the state. 159 */ 160 int 161 npf_state_etime(const npf_state_t *nst, const int proto) 162 { 163 const int state = nst->nst_state; 164 int timeout = 0; 165 166 switch (proto) { 167 case IPPROTO_TCP: 168 /* Pass to TCP state tracking engine. */ 169 timeout = npf_state_tcp_timeout(nst); 170 break; 171 case IPPROTO_UDP: 172 case IPPROTO_ICMP: 173 /* Generic. */ 174 timeout = npf_generic_timeout[state]; 175 break; 176 default: 177 KASSERT(false); 178 } 179 return timeout; 180 } 181 182 void 183 npf_state_dump(const npf_state_t *nst) 184 { 185 #if defined(DDB) || defined(_NPF_TESTING) 186 const npf_tcpstate_t *fst = &nst->nst_tcpst[0]; 187 const npf_tcpstate_t *tst = &nst->nst_tcpst[1]; 188 189 printf("\tstate (%p) %d:\n\t\t" 190 "F { end %u maxend %u mwin %u wscale %u }\n\t\t" 191 "T { end %u maxend %u mwin %u wscale %u }\n", 192 nst, nst->nst_state, 193 fst->nst_end, fst->nst_maxend, fst->nst_maxwin, fst->nst_wscale, 194 tst->nst_end, tst->nst_maxend, tst->nst_maxwin, tst->nst_wscale 195 ); 196 #endif 197 } 198
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