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/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 <netgraph/ng_message.h> 49 #include <netgraph/ng_parse.h> 50 #include <netgraph/ng_ipfw.h> 51 #include <netgraph/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 MALLOC(hpriv, hpriv_p, sizeof(*hpriv), M_NETGRAPH, M_NOWAIT | M_ZERO); 166 if (hpriv== NULL) 167 return (ENOMEM); 168 169 hpriv->hook = hook; 170 hpriv->rulenum = rulenum; 171 172 NG_HOOK_SET_PRIVATE(hook, hpriv); 173 174 return(0); 175 } 176 177 /* 178 * Set hooks into queueing mode, to avoid recursion between 179 * netgraph layer and ip_{input,output}. 180 */ 181 static int 182 ng_ipfw_connect(hook_p hook) 183 { 184 NG_HOOK_FORCE_QUEUE(hook); 185 return (0); 186 } 187 188 /* Look up hook by name */ 189 hook_p 190 ng_ipfw_findhook(node_p node, const char *name) 191 { 192 u_int16_t n; /* numeric representation of hook */ 193 char *endptr; 194 195 n = (u_int16_t)strtol(name, &endptr, 10); 196 if (*endptr != '\0') 197 return NULL; 198 return ng_ipfw_findhook1(node, n); 199 } 200 201 /* Look up hook by rule number */ 202 static hook_p 203 ng_ipfw_findhook1(node_p node, u_int16_t rulenum) 204 { 205 hook_p hook; 206 hpriv_p hpriv; 207 208 LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) { 209 hpriv = NG_HOOK_PRIVATE(hook); 210 if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum)) 211 return (hook); 212 } 213 214 return (NULL); 215 } 216 217 218 static int 219 ng_ipfw_rcvdata(hook_p hook, item_p item) 220 { 221 struct ng_ipfw_tag *ngit; 222 struct mbuf *m; 223 224 NGI_GET_M(item, m); 225 NG_FREE_ITEM(item); 226 227 if ((ngit = (struct ng_ipfw_tag *)m_tag_locate(m, NGM_IPFW_COOKIE, 0, 228 NULL)) == NULL) { 229 NG_FREE_M(m); 230 return (EINVAL); /* XXX: find smth better */ 231 }; 232 233 switch (ngit->dir) { 234 case NG_IPFW_OUT: 235 { 236 struct ip *ip; 237 238 if (m->m_len < sizeof(struct ip) && 239 (m = m_pullup(m, sizeof(struct ip))) == NULL) 240 return (EINVAL); 241 242 ip = mtod(m, struct ip *); 243 244 ip->ip_len = ntohs(ip->ip_len); 245 ip->ip_off = ntohs(ip->ip_off); 246 247 return ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL); 248 } 249 case NG_IPFW_IN: 250 ip_input(m); 251 return (0); 252 default: 253 panic("ng_ipfw_rcvdata: bad dir %u", ngit->dir); 254 } 255 256 /* not reached */ 257 return (0); 258 } 259 260 static int 261 ng_ipfw_input(struct mbuf **m0, int dir, struct ip_fw_args *fwa, int tee) 262 { 263 struct mbuf *m; 264 struct ng_ipfw_tag *ngit; 265 struct ip *ip; 266 hook_p hook; 267 int error = 0; 268 269 /* 270 * Node must be loaded and corresponding hook must be present. 271 */ 272 if (fw_node == NULL || 273 (hook = ng_ipfw_findhook1(fw_node, fwa->cookie)) == NULL) { 274 if (tee == 0) 275 m_freem(*m0); 276 return (ESRCH); /* no hook associated with this rule */ 277 } 278 279 /* 280 * We have two modes: in normal mode we add a tag to packet, which is 281 * important to return packet back to IP stack. In tee mode we make 282 * a copy of a packet and forward it into netgraph without a tag. 283 */ 284 if (tee == 0) { 285 m = *m0; 286 *m0 = NULL; /* it belongs now to netgraph */ 287 288 if ((ngit = (struct ng_ipfw_tag *)m_tag_alloc(NGM_IPFW_COOKIE, 289 0, TAGSIZ, M_NOWAIT|M_ZERO)) == NULL) { 290 m_freem(m); 291 return (ENOMEM); 292 } 293 ngit->rule = fwa->rule; 294 ngit->dir = dir; 295 ngit->ifp = fwa->oif; 296 m_tag_prepend(m, &ngit->mt); 297 298 } else 299 if ((m = m_dup(*m0, M_DONTWAIT)) == NULL) 300 return (ENOMEM); /* which is ignored */ 301 302 if (m->m_len < sizeof(struct ip) && 303 (m = m_pullup(m, sizeof(struct ip))) == NULL) 304 return (EINVAL); 305 306 ip = mtod(m, struct ip *); 307 ip->ip_len = htons(ip->ip_len); 308 ip->ip_off = htons(ip->ip_off); 309 310 NG_SEND_DATA_ONLY(error, hook, m); 311 312 return (error); 313 } 314 315 static int 316 ng_ipfw_shutdown(node_p node) 317 { 318 319 /* 320 * After our single node has been removed, 321 * the only thing that can be done is 322 * 'kldunload ng_ipfw.ko' 323 */ 324 ng_ipfw_input_p = NULL; 325 NG_NODE_UNREF(node); 326 return (0); 327 } 328 329 static int 330 ng_ipfw_disconnect(hook_p hook) 331 { 332 const hpriv_p hpriv = NG_HOOK_PRIVATE(hook); 333 334 FREE(hpriv, M_NETGRAPH); 335 NG_HOOK_SET_PRIVATE(hook, NULL); 336 337 return (0); 338 } 339