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