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 **, struct ip_fw_args *, bool); 76 77 /* We have only one node */ 78 static node_p fw_node; 79 80 /* Netgraph node type descriptor */ 81 static struct ng_type ng_ipfw_typestruct = { 82 .version = NG_ABI_VERSION, 83 .name = NG_IPFW_NODE_TYPE, 84 .mod_event = ng_ipfw_mod_event, 85 .constructor = ng_ipfw_constructor, 86 .shutdown = ng_ipfw_shutdown, 87 .newhook = ng_ipfw_newhook, 88 .connect = ng_ipfw_connect, 89 .findhook = ng_ipfw_findhook, 90 .rcvdata = ng_ipfw_rcvdata, 91 .disconnect = ng_ipfw_disconnect, 92 }; 93 NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct); 94 MODULE_DEPEND(ng_ipfw, ipfw, 3, 3, 3); 95 96 /* Information we store for each hook */ 97 struct ng_ipfw_hook_priv { 98 hook_p hook; 99 u_int16_t rulenum; 100 }; 101 typedef struct ng_ipfw_hook_priv *hpriv_p; 102 103 static int 104 ng_ipfw_mod_event(module_t mod, int event, void *data) 105 { 106 int error = 0; 107 108 switch (event) { 109 case MOD_LOAD: 110 111 if (ng_ipfw_input_p != NULL) { 112 error = EEXIST; 113 break; 114 } 115 116 /* Setup node without any private data */ 117 if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node)) 118 != 0) { 119 log(LOG_ERR, "%s: can't create ng_ipfw node", __func__); 120 break; 121 } 122 123 /* Try to name node */ 124 if (ng_name_node(fw_node, "ipfw") != 0) 125 log(LOG_WARNING, "%s: failed to name node \"ipfw\"", 126 __func__); 127 128 /* Register hook */ 129 ng_ipfw_input_p = ng_ipfw_input; 130 break; 131 132 case MOD_UNLOAD: 133 /* 134 * This won't happen if a node exists. 135 * ng_ipfw_input_p is already cleared. 136 */ 137 break; 138 139 default: 140 error = EOPNOTSUPP; 141 break; 142 } 143 144 return (error); 145 } 146 147 static int 148 ng_ipfw_constructor(node_p node) 149 { 150 return (EINVAL); /* Only one node */ 151 } 152 153 static int 154 ng_ipfw_newhook(node_p node, hook_p hook, const char *name) 155 { 156 hpriv_p hpriv; 157 u_int16_t rulenum; 158 const char *cp; 159 char *endptr; 160 161 /* Protect from leading zero */ 162 if (name[0] == '0' && name[1] != '\0') 163 return (EINVAL); 164 165 /* Check that name contains only digits */ 166 for (cp = name; *cp != '\0'; cp++) 167 if (!isdigit(*cp)) 168 return (EINVAL); 169 170 /* Convert it to integer */ 171 rulenum = (u_int16_t)strtol(name, &endptr, 10); 172 if (*endptr != '\0') 173 return (EINVAL); 174 175 /* Allocate memory for this hook's private data */ 176 hpriv = malloc(sizeof(*hpriv), M_NETGRAPH, M_NOWAIT | M_ZERO); 177 if (hpriv== NULL) 178 return (ENOMEM); 179 180 hpriv->hook = hook; 181 hpriv->rulenum = rulenum; 182 183 NG_HOOK_SET_PRIVATE(hook, hpriv); 184 185 return(0); 186 } 187 188 /* 189 * Set hooks into queueing mode, to avoid recursion between 190 * netgraph layer and ip_{input,output}. 191 */ 192 static int 193 ng_ipfw_connect(hook_p hook) 194 { 195 NG_HOOK_FORCE_QUEUE(hook); 196 return (0); 197 } 198 199 /* Look up hook by name */ 200 static hook_p 201 ng_ipfw_findhook(node_p node, const char *name) 202 { 203 u_int16_t n; /* numeric representation of hook */ 204 char *endptr; 205 206 n = (u_int16_t)strtol(name, &endptr, 10); 207 if (*endptr != '\0') 208 return NULL; 209 return ng_ipfw_findhook1(node, n); 210 } 211 212 /* Look up hook by rule number */ 213 static hook_p 214 ng_ipfw_findhook1(node_p node, u_int16_t rulenum) 215 { 216 hook_p hook; 217 hpriv_p hpriv; 218 219 LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) { 220 hpriv = NG_HOOK_PRIVATE(hook); 221 if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum)) 222 return (hook); 223 } 224 225 return (NULL); 226 } 227 228 static int 229 ng_ipfw_rcvdata(hook_p hook, item_p item) 230 { 231 struct m_tag *tag; 232 struct ipfw_rule_ref *r; 233 struct mbuf *m; 234 struct ip *ip; 235 236 NGI_GET_M(item, m); 237 NG_FREE_ITEM(item); 238 239 tag = m_tag_locate(m, MTAG_IPFW_RULE, 0, NULL); 240 if (tag == NULL) { 241 NG_FREE_M(m); 242 return (EINVAL); /* XXX: find smth better */ 243 } 244 245 if (m->m_len < sizeof(struct ip) && 246 (m = m_pullup(m, sizeof(struct ip))) == NULL) 247 return (ENOBUFS); 248 249 ip = mtod(m, struct ip *); 250 251 r = (struct ipfw_rule_ref *)(tag + 1); 252 if (r->info & IPFW_INFO_IN) { 253 switch (ip->ip_v) { 254 #ifdef INET 255 case IPVERSION: 256 ip_input(m); 257 return (0); 258 #endif 259 #ifdef INET6 260 case IPV6_VERSION >> 4: 261 ip6_input(m); 262 return (0); 263 #endif 264 } 265 } else { 266 switch (ip->ip_v) { 267 #ifdef INET 268 case IPVERSION: 269 return (ip_output(m, NULL, NULL, IP_FORWARDING, 270 NULL, NULL)); 271 #endif 272 #ifdef INET6 273 case IPV6_VERSION >> 4: 274 return (ip6_output(m, NULL, NULL, 0, NULL, 275 NULL, NULL)); 276 #endif 277 } 278 } 279 280 /* unknown IP protocol version */ 281 NG_FREE_M(m); 282 return (EPROTONOSUPPORT); 283 } 284 285 static int 286 ng_ipfw_input(struct mbuf **m0, struct ip_fw_args *fwa, bool tee) 287 { 288 struct mbuf *m; 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 == false) { 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 |= (fwa->flags & IPFW_ARGS_IN) ? 320 IPFW_INFO_IN : IPFW_INFO_OUT; 321 m_tag_prepend(m, tag); 322 323 } else 324 if ((m = m_dup(*m0, M_NOWAIT)) == NULL) 325 return (ENOMEM); /* which is ignored */ 326 327 if (m->m_len < sizeof(struct ip) && 328 (m = m_pullup(m, sizeof(struct ip))) == NULL) 329 return (EINVAL); 330 331 NG_SEND_DATA_ONLY(error, hook, m); 332 333 return (error); 334 } 335 336 static int 337 ng_ipfw_shutdown(node_p node) 338 { 339 340 /* 341 * After our single node has been removed, 342 * the only thing that can be done is 343 * 'kldunload ng_ipfw.ko' 344 */ 345 ng_ipfw_input_p = NULL; 346 NG_NODE_UNREF(node); 347 return (0); 348 } 349 350 static int 351 ng_ipfw_disconnect(hook_p hook) 352 { 353 const hpriv_p hpriv = NG_HOOK_PRIVATE(hook); 354 355 free(hpriv, M_NETGRAPH); 356 NG_HOOK_SET_PRIVATE(hook, NULL); 357 358 return (0); 359 } 360