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 <sys/param.h> 30 #include <sys/systm.h> 31 #include <sys/kernel.h> 32 #include <sys/lock.h> 33 #include <sys/mbuf.h> 34 #include <sys/malloc.h> 35 #include <sys/ctype.h> 36 #include <sys/errno.h> 37 #include <sys/rwlock.h> 38 #include <sys/socket.h> 39 #include <sys/syslog.h> 40 41 #include <net/if.h> 42 43 #include <netinet/in.h> 44 #include <netinet/in_systm.h> 45 #include <netinet/in_var.h> 46 #include <netinet/ip_fw.h> 47 #include <netinet/ip.h> 48 #include <netinet/ip_var.h> 49 50 #include <netgraph/ng_message.h> 51 #include <netgraph/ng_parse.h> 52 #include <netgraph/ng_ipfw.h> 53 #include <netgraph/netgraph.h> 54 55 static int ng_ipfw_mod_event(module_t mod, int event, void *data); 56 static ng_constructor_t ng_ipfw_constructor; 57 static ng_shutdown_t ng_ipfw_shutdown; 58 static ng_newhook_t ng_ipfw_newhook; 59 static ng_connect_t ng_ipfw_connect; 60 static ng_findhook_t ng_ipfw_findhook; 61 static ng_rcvdata_t ng_ipfw_rcvdata; 62 static ng_disconnect_t ng_ipfw_disconnect; 63 64 static hook_p ng_ipfw_findhook1(node_p, u_int16_t ); 65 static int ng_ipfw_input(struct mbuf **, int, struct ip_fw_args *, 66 int); 67 68 /* We have only one node */ 69 static node_p fw_node; 70 71 /* Netgraph node type descriptor */ 72 static struct ng_type ng_ipfw_typestruct = { 73 .version = NG_ABI_VERSION, 74 .name = NG_IPFW_NODE_TYPE, 75 .mod_event = ng_ipfw_mod_event, 76 .constructor = ng_ipfw_constructor, 77 .shutdown = ng_ipfw_shutdown, 78 .newhook = ng_ipfw_newhook, 79 .connect = ng_ipfw_connect, 80 .findhook = ng_ipfw_findhook, 81 .rcvdata = ng_ipfw_rcvdata, 82 .disconnect = ng_ipfw_disconnect, 83 }; 84 NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct); 85 MODULE_DEPEND(ng_ipfw, ipfw, 2, 2, 2); 86 87 /* Information we store for each hook */ 88 struct ng_ipfw_hook_priv { 89 hook_p hook; 90 u_int16_t rulenum; 91 }; 92 typedef struct ng_ipfw_hook_priv *hpriv_p; 93 94 static int 95 ng_ipfw_mod_event(module_t mod, int event, void *data) 96 { 97 int error = 0; 98 99 switch (event) { 100 case MOD_LOAD: 101 102 if (ng_ipfw_input_p != NULL) { 103 error = EEXIST; 104 break; 105 } 106 107 /* Setup node without any private data */ 108 if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node)) 109 != 0) { 110 log(LOG_ERR, "%s: can't create ng_ipfw node", __func__); 111 break; 112 }; 113 114 /* Try to name node */ 115 if (ng_name_node(fw_node, "ipfw") != 0) 116 log(LOG_WARNING, "%s: failed to name node \"ipfw\"", 117 __func__); 118 119 /* Register hook */ 120 ng_ipfw_input_p = ng_ipfw_input; 121 break; 122 123 case MOD_UNLOAD: 124 /* 125 * This won't happen if a node exists. 126 * ng_ipfw_input_p is already cleared. 127 */ 128 break; 129 130 default: 131 error = EOPNOTSUPP; 132 break; 133 } 134 135 return (error); 136 } 137 138 static int 139 ng_ipfw_constructor(node_p node) 140 { 141 return (EINVAL); /* Only one node */ 142 } 143 144 static int 145 ng_ipfw_newhook(node_p node, hook_p hook, const char *name) 146 { 147 hpriv_p hpriv; 148 u_int16_t rulenum; 149 const char *cp; 150 char *endptr; 151 152 /* Protect from leading zero */ 153 if (name[0] == '0' && name[1] != '\0') 154 return (EINVAL); 155 156 /* Check that name contains only digits */ 157 for (cp = name; *cp != '\0'; cp++) 158 if (!isdigit(*cp)) 159 return (EINVAL); 160 161 /* Convert it to integer */ 162 rulenum = (u_int16_t)strtol(name, &endptr, 10); 163 if (*endptr != '\0') 164 return (EINVAL); 165 166 /* Allocate memory for this hook's private data */ 167 hpriv = malloc(sizeof(*hpriv), M_NETGRAPH, M_NOWAIT | M_ZERO); 168 if (hpriv== NULL) 169 return (ENOMEM); 170 171 hpriv->hook = hook; 172 hpriv->rulenum = rulenum; 173 174 NG_HOOK_SET_PRIVATE(hook, hpriv); 175 176 return(0); 177 } 178 179 /* 180 * Set hooks into queueing mode, to avoid recursion between 181 * netgraph layer and ip_{input,output}. 182 */ 183 static int 184 ng_ipfw_connect(hook_p hook) 185 { 186 NG_HOOK_FORCE_QUEUE(hook); 187 return (0); 188 } 189 190 /* Look up hook by name */ 191 hook_p 192 ng_ipfw_findhook(node_p node, const char *name) 193 { 194 u_int16_t n; /* numeric representation of hook */ 195 char *endptr; 196 197 n = (u_int16_t)strtol(name, &endptr, 10); 198 if (*endptr != '\0') 199 return NULL; 200 return ng_ipfw_findhook1(node, n); 201 } 202 203 /* Look up hook by rule number */ 204 static hook_p 205 ng_ipfw_findhook1(node_p node, u_int16_t rulenum) 206 { 207 hook_p hook; 208 hpriv_p hpriv; 209 210 LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) { 211 hpriv = NG_HOOK_PRIVATE(hook); 212 if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum)) 213 return (hook); 214 } 215 216 return (NULL); 217 } 218 219 220 static int 221 ng_ipfw_rcvdata(hook_p hook, item_p item) 222 { 223 struct ng_ipfw_tag *ngit; 224 struct mbuf *m; 225 226 NGI_GET_M(item, m); 227 NG_FREE_ITEM(item); 228 229 if ((ngit = (struct ng_ipfw_tag *)m_tag_locate(m, NGM_IPFW_COOKIE, 0, 230 NULL)) == NULL) { 231 NG_FREE_M(m); 232 return (EINVAL); /* XXX: find smth better */ 233 }; 234 235 switch (ngit->dir) { 236 case NG_IPFW_OUT: 237 { 238 struct ip *ip; 239 240 if (m->m_len < sizeof(struct ip) && 241 (m = m_pullup(m, sizeof(struct ip))) == NULL) 242 return (EINVAL); 243 244 ip = mtod(m, struct ip *); 245 246 ip->ip_len = ntohs(ip->ip_len); 247 ip->ip_off = ntohs(ip->ip_off); 248 249 return ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL); 250 } 251 case NG_IPFW_IN: 252 ip_input(m); 253 return (0); 254 default: 255 panic("ng_ipfw_rcvdata: bad dir %u", ngit->dir); 256 } 257 258 /* not reached */ 259 return (0); 260 } 261 262 static int 263 ng_ipfw_input(struct mbuf **m0, int dir, struct ip_fw_args *fwa, int tee) 264 { 265 struct mbuf *m; 266 struct ng_ipfw_tag *ngit; 267 struct ip *ip; 268 hook_p hook; 269 int error = 0; 270 271 /* 272 * Node must be loaded and corresponding hook must be present. 273 */ 274 if (fw_node == NULL || 275 (hook = ng_ipfw_findhook1(fw_node, fwa->cookie)) == NULL) { 276 if (tee == 0) 277 m_freem(*m0); 278 return (ESRCH); /* no hook associated with this rule */ 279 } 280 281 /* 282 * We have two modes: in normal mode we add a tag to packet, which is 283 * important to return packet back to IP stack. In tee mode we make 284 * a copy of a packet and forward it into netgraph without a tag. 285 */ 286 if (tee == 0) { 287 m = *m0; 288 *m0 = NULL; /* it belongs now to netgraph */ 289 290 if ((ngit = (struct ng_ipfw_tag *)m_tag_alloc(NGM_IPFW_COOKIE, 291 0, TAGSIZ, M_NOWAIT|M_ZERO)) == NULL) { 292 m_freem(m); 293 return (ENOMEM); 294 } 295 ngit->rule = fwa->rule; 296 ngit->dir = dir; 297 ngit->ifp = fwa->oif; 298 m_tag_prepend(m, &ngit->mt); 299 300 } else 301 if ((m = m_dup(*m0, M_DONTWAIT)) == NULL) 302 return (ENOMEM); /* which is ignored */ 303 304 if (m->m_len < sizeof(struct ip) && 305 (m = m_pullup(m, sizeof(struct ip))) == NULL) 306 return (EINVAL); 307 308 ip = mtod(m, struct ip *); 309 ip->ip_len = htons(ip->ip_len); 310 ip->ip_off = htons(ip->ip_off); 311 312 NG_SEND_DATA_ONLY(error, hook, m); 313 314 return (error); 315 } 316 317 static int 318 ng_ipfw_shutdown(node_p node) 319 { 320 321 /* 322 * After our single node has been removed, 323 * the only thing that can be done is 324 * 'kldunload ng_ipfw.ko' 325 */ 326 ng_ipfw_input_p = NULL; 327 NG_NODE_UNREF(node); 328 return (0); 329 } 330 331 static int 332 ng_ipfw_disconnect(hook_p hook) 333 { 334 const hpriv_p hpriv = NG_HOOK_PRIVATE(hook); 335 336 free(hpriv, M_NETGRAPH); 337 NG_HOOK_SET_PRIVATE(hook, NULL); 338 339 return (0); 340 } 341