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: src/sys/netgraph/ng_ipfw.c,v 1.9 2006/02/14 15:22:24 ru Exp $ 27 */ 28 29 #include <sys/param.h> 30 #include <sys/systm.h> 31 #include <sys/kernel.h> 32 #include <sys/mbuf.h> 33 #include <sys/malloc.h> 34 #include <sys/ctype.h> 35 #include <sys/errno.h> 36 #include <sys/socket.h> 37 #include <sys/syslog.h> 38 39 #include <net/if.h> 40 41 #include <netinet/in.h> 42 #include <netinet/in_systm.h> 43 #include <netinet/in_var.h> 44 #include <netinet/ip_fw.h> 45 #include <netinet/ip.h> 46 #include <netinet/ip_var.h> 47 48 #include "ng_message.h" 49 #include "ng_parse.h" 50 #include "ng_ipfw.h" 51 #include "netgraph.h" 52 53 static int ng_ipfw_mod_event(module_t mod, int event, void *data); 54 static ng_constructor_t ng_ipfw_constructor; 55 static ng_shutdown_t ng_ipfw_shutdown; 56 static ng_newhook_t ng_ipfw_newhook; 57 static ng_connect_t ng_ipfw_connect; 58 static ng_findhook_t ng_ipfw_findhook; 59 static ng_rcvdata_t ng_ipfw_rcvdata; 60 static ng_disconnect_t ng_ipfw_disconnect; 61 62 static hook_p ng_ipfw_findhook1(node_p, u_int16_t ); 63 static int ng_ipfw_input(struct mbuf **, int, struct ip_fw_args *, 64 int); 65 66 /* We have only one node */ 67 static node_p fw_node; 68 69 /* Netgraph node type descriptor */ 70 static struct ng_type ng_ipfw_typestruct = { 71 .version = NG_ABI_VERSION, 72 .name = NG_IPFW_NODE_TYPE, 73 .mod_event = ng_ipfw_mod_event, 74 .constructor = ng_ipfw_constructor, 75 .shutdown = ng_ipfw_shutdown, 76 .newhook = ng_ipfw_newhook, 77 .connect = ng_ipfw_connect, 78 .findhook = ng_ipfw_findhook, 79 .rcvdata = ng_ipfw_rcvdata, 80 .disconnect = ng_ipfw_disconnect, 81 }; 82 NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct); 83 MODULE_DEPEND(ng_ipfw, ipfw, 2, 2, 2); 84 85 /* Information we store for each hook */ 86 struct ng_ipfw_hook_priv { 87 hook_p hook; 88 u_int16_t rulenum; 89 }; 90 typedef struct ng_ipfw_hook_priv *hpriv_p; 91 92 static int 93 ng_ipfw_mod_event(module_t mod, int event, void *data) 94 { 95 int error = 0; 96 97 switch (event) { 98 case MOD_LOAD: 99 100 if (ng_ipfw_input_p != NULL) { 101 error = EEXIST; 102 break; 103 } 104 105 /* Setup node without any private data */ 106 if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node)) 107 != 0) { 108 log(LOG_ERR, "%s: can't create ng_ipfw node", __func__); 109 break; 110 } 111 112 /* Try to name node */ 113 if (ng_name_node(fw_node, "ipfw") != 0) 114 log(LOG_WARNING, "%s: failed to name node \"ipfw\"", 115 __func__); 116 117 /* Register hook */ 118 ng_ipfw_input_p = ng_ipfw_input; 119 break; 120 121 case MOD_UNLOAD: 122 /* 123 * This won't happen if a node exists. 124 * ng_ipfw_input_p is already cleared. 125 */ 126 break; 127 128 default: 129 error = EOPNOTSUPP; 130 break; 131 } 132 133 return (error); 134 } 135 136 static int 137 ng_ipfw_constructor(node_p node) 138 { 139 return (EINVAL); /* Only one node */ 140 } 141 142 static int 143 ng_ipfw_newhook(node_p node, hook_p hook, const char *name) 144 { 145 hpriv_p hpriv; 146 u_int16_t rulenum; 147 const char *cp; 148 char *endptr; 149 150 /* Protect from leading zero */ 151 if (name[0] == '0' && name[1] != '\0') 152 return (EINVAL); 153 154 /* Check that name contains only digits */ 155 for (cp = name; *cp != '\0'; cp++) 156 if (!isdigit(*cp)) 157 return (EINVAL); 158 159 /* Convert it to integer */ 160 rulenum = (u_int16_t)strtol(name, &endptr, 10); 161 if (*endptr != '\0') 162 return (EINVAL); 163 164 /* Allocate memory for this hook's private data */ 165 hpriv = kmalloc(sizeof(*hpriv), M_NETGRAPH, 166 M_WAITOK | M_NULLOK | M_ZERO); 167 if (hpriv== NULL) 168 return (ENOMEM); 169 170 hpriv->hook = hook; 171 hpriv->rulenum = rulenum; 172 173 NG_HOOK_SET_PRIVATE(hook, hpriv); 174 175 return(0); 176 } 177 178 /* 179 * Set hooks into queueing mode, to avoid recursion between 180 * netgraph layer and ip_{input,output}. 181 */ 182 static int 183 ng_ipfw_connect(hook_p hook) 184 { 185 NG_HOOK_FORCE_QUEUE(hook); 186 return (0); 187 } 188 189 /* Look up hook by name */ 190 hook_p 191 ng_ipfw_findhook(node_p node, const char *name) 192 { 193 u_int16_t n; /* numeric representation of hook */ 194 char *endptr; 195 196 n = (u_int16_t)strtol(name, &endptr, 10); 197 if (*endptr != '\0') 198 return NULL; 199 return ng_ipfw_findhook1(node, n); 200 } 201 202 /* Look up hook by rule number */ 203 static hook_p 204 ng_ipfw_findhook1(node_p node, u_int16_t rulenum) 205 { 206 hook_p hook; 207 hpriv_p hpriv; 208 209 LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) { 210 hpriv = NG_HOOK_PRIVATE(hook); 211 if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum)) 212 return (hook); 213 } 214 215 return (NULL); 216 } 217 218 219 static int 220 ng_ipfw_rcvdata(hook_p hook, item_p item) 221 { 222 struct ng_ipfw_tag *ngit; 223 struct mbuf *m; 224 225 NGI_GET_M(item, m); 226 NG_FREE_ITEM(item); 227 228 if ((ngit = (struct ng_ipfw_tag *)m_tag_locate(m, NGM_IPFW_COOKIE, 0, 229 NULL)) == NULL) { 230 NG_FREE_M(m); 231 return (EINVAL); /* XXX: find smth better */ 232 } 233 234 switch (ngit->dir) { 235 case NG_IPFW_OUT: 236 { 237 struct ip *ip; 238 239 if (m->m_len < sizeof(struct ip) && 240 (m = m_pullup(m, sizeof(struct ip))) == NULL) 241 return (EINVAL); 242 243 ip = mtod(m, struct ip *); 244 245 return ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL); 246 } 247 case NG_IPFW_IN: 248 ip_input(m); 249 return (0); 250 default: 251 panic("ng_ipfw_rcvdata: bad dir %u", ngit->dir); 252 } 253 254 /* not reached */ 255 return (0); 256 } 257 258 static int 259 ng_ipfw_input(struct mbuf **m0, int dir, struct ip_fw_args *fwa, int tee) 260 { 261 struct mbuf *m; 262 struct ng_ipfw_tag *ngit; 263 struct ip *ip; 264 hook_p hook; 265 int error = 0; 266 267 /* 268 * Node must be loaded and corresponding hook must be present. 269 */ 270 if (fw_node == NULL || 271 (hook = ng_ipfw_findhook1(fw_node, fwa->cookie)) == NULL) { 272 if (tee == 0) 273 m_freem(*m0); 274 return (ESRCH); /* no hook associated with this rule */ 275 } 276 277 /* 278 * We have two modes: in normal mode we add a tag to packet, which is 279 * important to return packet back to IP stack. In tee mode we make 280 * a copy of a packet and forward it into netgraph without a tag. 281 */ 282 if (tee == 0) { 283 m = *m0; 284 *m0 = NULL; /* it belongs now to netgraph */ 285 286 if ((ngit = (struct ng_ipfw_tag *)m_tag_alloc(NGM_IPFW_COOKIE, 287 0, TAGSIZ, M_NOWAIT)) == NULL) { 288 m_freem(m); 289 return (ENOMEM); 290 } 291 ngit->rule = fwa->rule; 292 ngit->dir = dir; 293 ngit->ifp = fwa->oif; 294 m_tag_prepend(m, &ngit->mt); 295 296 } else 297 if ((m = m_dup(*m0, M_NOWAIT)) == NULL) 298 return (ENOMEM); /* which is ignored */ 299 300 if (m->m_len < sizeof(struct ip) && 301 (m = m_pullup(m, sizeof(struct ip))) == NULL) 302 return (EINVAL); 303 304 ip = mtod(m, struct ip *); 305 306 NG_SEND_DATA_ONLY(error, hook, m); 307 308 return (error); 309 } 310 311 static int 312 ng_ipfw_shutdown(node_p node) 313 { 314 315 /* 316 * After our single node has been removed, 317 * the only thing that can be done is 318 * 'kldunload ng_ipfw.ko' 319 */ 320 ng_ipfw_input_p = NULL; 321 NG_NODE_UNREF(node); 322 return (0); 323 } 324 325 static int 326 ng_ipfw_disconnect(hook_p hook) 327 { 328 const hpriv_p hpriv = NG_HOOK_PRIVATE(hook); 329 330 kfree(hpriv, M_NETGRAPH); 331 NG_HOOK_SET_PRIVATE(hook, NULL); 332 333 return (0); 334 } 335