1 /*- 2 * Copyright 2005, Gleb Smirnoff <glebius@FreeBSD.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD$ 27 */ 28 29 #include "opt_inet.h" 30 #include "opt_inet6.h" 31 32 #include <sys/param.h> 33 #include <sys/systm.h> 34 #include <sys/kernel.h> 35 #include <sys/lock.h> 36 #include <sys/mbuf.h> 37 #include <sys/malloc.h> 38 #include <sys/ctype.h> 39 #include <sys/errno.h> 40 #include <sys/rwlock.h> 41 #include <sys/socket.h> 42 #include <sys/syslog.h> 43 44 #include <net/if.h> 45 46 #include <netinet/in.h> 47 #include <netinet/in_systm.h> 48 #include <netinet/in_var.h> 49 #include <netinet/ip_var.h> 50 #include <netinet/ip_fw.h> 51 #include <netinet/ipfw/ip_fw_private.h> 52 #include <netinet/ip.h> 53 #include <netinet/ip6.h> 54 #include <netinet6/ip6_var.h> 55 56 #include <netgraph/ng_message.h> 57 #include <netgraph/ng_parse.h> 58 #include <netgraph/ng_ipfw.h> 59 #include <netgraph/netgraph.h> 60 61 static int ng_ipfw_mod_event(module_t mod, int event, void *data); 62 static ng_constructor_t ng_ipfw_constructor; 63 static ng_shutdown_t ng_ipfw_shutdown; 64 static ng_newhook_t ng_ipfw_newhook; 65 static ng_connect_t ng_ipfw_connect; 66 static ng_findhook_t ng_ipfw_findhook; 67 static ng_rcvdata_t ng_ipfw_rcvdata; 68 static ng_disconnect_t ng_ipfw_disconnect; 69 70 static hook_p ng_ipfw_findhook1(node_p, u_int16_t ); 71 static int ng_ipfw_input(struct mbuf **, int, struct ip_fw_args *, 72 int); 73 74 /* We have only one node */ 75 static node_p fw_node; 76 77 /* Netgraph node type descriptor */ 78 static struct ng_type ng_ipfw_typestruct = { 79 .version = NG_ABI_VERSION, 80 .name = NG_IPFW_NODE_TYPE, 81 .mod_event = ng_ipfw_mod_event, 82 .constructor = ng_ipfw_constructor, 83 .shutdown = ng_ipfw_shutdown, 84 .newhook = ng_ipfw_newhook, 85 .connect = ng_ipfw_connect, 86 .findhook = ng_ipfw_findhook, 87 .rcvdata = ng_ipfw_rcvdata, 88 .disconnect = ng_ipfw_disconnect, 89 }; 90 NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct); 91 MODULE_DEPEND(ng_ipfw, ipfw, 2, 2, 2); 92 93 /* Information we store for each hook */ 94 struct ng_ipfw_hook_priv { 95 hook_p hook; 96 u_int16_t rulenum; 97 }; 98 typedef struct ng_ipfw_hook_priv *hpriv_p; 99 100 static int 101 ng_ipfw_mod_event(module_t mod, int event, void *data) 102 { 103 int error = 0; 104 105 switch (event) { 106 case MOD_LOAD: 107 108 if (ng_ipfw_input_p != NULL) { 109 error = EEXIST; 110 break; 111 } 112 113 /* Setup node without any private data */ 114 if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node)) 115 != 0) { 116 log(LOG_ERR, "%s: can't create ng_ipfw node", __func__); 117 break; 118 }; 119 120 /* Try to name node */ 121 if (ng_name_node(fw_node, "ipfw") != 0) 122 log(LOG_WARNING, "%s: failed to name node \"ipfw\"", 123 __func__); 124 125 /* Register hook */ 126 ng_ipfw_input_p = ng_ipfw_input; 127 break; 128 129 case MOD_UNLOAD: 130 /* 131 * This won't happen if a node exists. 132 * ng_ipfw_input_p is already cleared. 133 */ 134 break; 135 136 default: 137 error = EOPNOTSUPP; 138 break; 139 } 140 141 return (error); 142 } 143 144 static int 145 ng_ipfw_constructor(node_p node) 146 { 147 return (EINVAL); /* Only one node */ 148 } 149 150 static int 151 ng_ipfw_newhook(node_p node, hook_p hook, const char *name) 152 { 153 hpriv_p hpriv; 154 u_int16_t rulenum; 155 const char *cp; 156 char *endptr; 157 158 /* Protect from leading zero */ 159 if (name[0] == '0' && name[1] != '\0') 160 return (EINVAL); 161 162 /* Check that name contains only digits */ 163 for (cp = name; *cp != '\0'; cp++) 164 if (!isdigit(*cp)) 165 return (EINVAL); 166 167 /* Convert it to integer */ 168 rulenum = (u_int16_t)strtol(name, &endptr, 10); 169 if (*endptr != '\0') 170 return (EINVAL); 171 172 /* Allocate memory for this hook's private data */ 173 hpriv = malloc(sizeof(*hpriv), M_NETGRAPH, M_NOWAIT | M_ZERO); 174 if (hpriv== NULL) 175 return (ENOMEM); 176 177 hpriv->hook = hook; 178 hpriv->rulenum = rulenum; 179 180 NG_HOOK_SET_PRIVATE(hook, hpriv); 181 182 return(0); 183 } 184 185 /* 186 * Set hooks into queueing mode, to avoid recursion between 187 * netgraph layer and ip_{input,output}. 188 */ 189 static int 190 ng_ipfw_connect(hook_p hook) 191 { 192 NG_HOOK_FORCE_QUEUE(hook); 193 return (0); 194 } 195 196 /* Look up hook by name */ 197 hook_p 198 ng_ipfw_findhook(node_p node, const char *name) 199 { 200 u_int16_t n; /* numeric representation of hook */ 201 char *endptr; 202 203 n = (u_int16_t)strtol(name, &endptr, 10); 204 if (*endptr != '\0') 205 return NULL; 206 return ng_ipfw_findhook1(node, n); 207 } 208 209 /* Look up hook by rule number */ 210 static hook_p 211 ng_ipfw_findhook1(node_p node, u_int16_t rulenum) 212 { 213 hook_p hook; 214 hpriv_p hpriv; 215 216 LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) { 217 hpriv = NG_HOOK_PRIVATE(hook); 218 if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum)) 219 return (hook); 220 } 221 222 return (NULL); 223 } 224 225 226 static int 227 ng_ipfw_rcvdata(hook_p hook, item_p item) 228 { 229 struct m_tag *tag; 230 struct ipfw_rule_ref *r; 231 struct mbuf *m; 232 struct ip *ip; 233 234 NGI_GET_M(item, m); 235 NG_FREE_ITEM(item); 236 237 tag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL); 238 if (tag == NULL) { 239 NG_FREE_M(m); 240 return (EINVAL); /* XXX: find smth better */ 241 }; 242 243 if (m->m_len < sizeof(struct ip) && 244 (m = m_pullup(m, sizeof(struct ip))) == NULL) 245 return (ENOBUFS); 246 247 ip = mtod(m, struct ip *); 248 249 r = (struct ipfw_rule_ref *)(tag + 1); 250 if (r->info & IPFW_INFO_IN) { 251 switch (ip->ip_v) { 252 #ifdef INET 253 case IPVERSION: 254 ip_input(m); 255 return (0); 256 #endif 257 #ifdef INET6 258 case IPV6_VERSION >> 4: 259 ip6_input(m); 260 return (0); 261 #endif 262 } 263 } else { 264 switch (ip->ip_v) { 265 #ifdef INET 266 case IPVERSION: 267 SET_HOST_IPLEN(ip); 268 return (ip_output(m, NULL, NULL, IP_FORWARDING, 269 NULL, NULL)); 270 #endif 271 #ifdef INET6 272 case IPV6_VERSION >> 4: 273 return (ip6_output(m, NULL, NULL, 0, NULL, 274 NULL, NULL)); 275 #endif 276 } 277 } 278 279 /* unknown IP protocol version */ 280 NG_FREE_M(m); 281 return (EPROTONOSUPPORT); 282 } 283 284 static int 285 ng_ipfw_input(struct mbuf **m0, int dir, struct ip_fw_args *fwa, int tee) 286 { 287 struct mbuf *m; 288 struct ip *ip; 289 hook_p hook; 290 int error = 0; 291 292 /* 293 * Node must be loaded and corresponding hook must be present. 294 */ 295 if (fw_node == NULL || 296 (hook = ng_ipfw_findhook1(fw_node, fwa->rule.info)) == NULL) 297 return (ESRCH); /* no hook associated with this rule */ 298 299 /* 300 * We have two modes: in normal mode we add a tag to packet, which is 301 * important to return packet back to IP stack. In tee mode we make 302 * a copy of a packet and forward it into netgraph without a tag. 303 */ 304 if (tee == 0) { 305 struct m_tag *tag; 306 struct ipfw_rule_ref *r; 307 m = *m0; 308 *m0 = NULL; /* it belongs now to netgraph */ 309 310 tag = m_tag_alloc(MTAG_IPFW_RULE, 0, sizeof(*r), 311 M_NOWAIT|M_ZERO); 312 if (tag == NULL) { 313 m_freem(m); 314 return (ENOMEM); 315 } 316 r = (struct ipfw_rule_ref *)(tag + 1); 317 *r = fwa->rule; 318 r->info &= IPFW_ONEPASS; /* keep this info */ 319 r->info |= dir ? IPFW_INFO_IN : IPFW_INFO_OUT; 320 m_tag_prepend(m, tag); 321 322 } else 323 if ((m = m_dup(*m0, M_DONTWAIT)) == NULL) 324 return (ENOMEM); /* which is ignored */ 325 326 if (m->m_len < sizeof(struct ip) && 327 (m = m_pullup(m, sizeof(struct ip))) == NULL) 328 return (EINVAL); 329 330 ip = mtod(m, struct ip *); 331 332 NG_SEND_DATA_ONLY(error, hook, m); 333 334 return (error); 335 } 336 337 static int 338 ng_ipfw_shutdown(node_p node) 339 { 340 341 /* 342 * After our single node has been removed, 343 * the only thing that can be done is 344 * 'kldunload ng_ipfw.ko' 345 */ 346 ng_ipfw_input_p = NULL; 347 NG_NODE_UNREF(node); 348 return (0); 349 } 350 351 static int 352 ng_ipfw_disconnect(hook_p hook) 353 { 354 const hpriv_p hpriv = NG_HOOK_PRIVATE(hook); 355 356 free(hpriv, M_NETGRAPH); 357 NG_HOOK_SET_PRIVATE(hook, NULL); 358 359 return (0); 360 } 361