1 /*- 2 * ng_etf.c Ethertype filter 3 */ 4 5 /*- 6 * Copyright (c) 2001, FreeBSD Incorporated 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice unmodified, this list of conditions, and the following 14 * disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 * Author: Julian Elischer <julian@freebsd.org> 32 * 33 * $FreeBSD$ 34 */ 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/kernel.h> 39 #include <sys/mbuf.h> 40 #include <sys/malloc.h> 41 #include <sys/ctype.h> 42 #include <sys/errno.h> 43 #include <sys/queue.h> 44 #include <sys/syslog.h> 45 46 #include <net/ethernet.h> 47 48 #include <netgraph/ng_message.h> 49 #include <netgraph/ng_parse.h> 50 #include <netgraph/ng_etf.h> 51 #include <netgraph/netgraph.h> 52 53 /* If you do complicated mallocs you may want to do this */ 54 /* and use it for your mallocs */ 55 #ifdef NG_SEPARATE_MALLOC 56 static MALLOC_DEFINE(M_NETGRAPH_ETF, "netgraph_etf", "netgraph etf node "); 57 #else 58 #define M_NETGRAPH_ETF M_NETGRAPH 59 #endif 60 61 /* 62 * This section contains the netgraph method declarations for the 63 * etf node. These methods define the netgraph 'type'. 64 */ 65 66 static ng_constructor_t ng_etf_constructor; 67 static ng_rcvmsg_t ng_etf_rcvmsg; 68 static ng_shutdown_t ng_etf_shutdown; 69 static ng_newhook_t ng_etf_newhook; 70 static ng_rcvdata_t ng_etf_rcvdata; /* note these are both ng_rcvdata_t */ 71 static ng_disconnect_t ng_etf_disconnect; 72 73 /* Parse type for struct ng_etfstat */ 74 static const struct ng_parse_struct_field ng_etf_stat_type_fields[] 75 = NG_ETF_STATS_TYPE_INFO; 76 static const struct ng_parse_type ng_etf_stat_type = { 77 &ng_parse_struct_type, 78 &ng_etf_stat_type_fields 79 }; 80 /* Parse type for struct ng_setfilter */ 81 static const struct ng_parse_struct_field ng_etf_filter_type_fields[] 82 = NG_ETF_FILTER_TYPE_INFO; 83 static const struct ng_parse_type ng_etf_filter_type = { 84 &ng_parse_struct_type, 85 &ng_etf_filter_type_fields 86 }; 87 88 /* List of commands and how to convert arguments to/from ASCII */ 89 static const struct ng_cmdlist ng_etf_cmdlist[] = { 90 { 91 NGM_ETF_COOKIE, 92 NGM_ETF_GET_STATUS, 93 "getstatus", 94 NULL, 95 &ng_etf_stat_type, 96 }, 97 { 98 NGM_ETF_COOKIE, 99 NGM_ETF_SET_FLAG, 100 "setflag", 101 &ng_parse_int32_type, 102 NULL 103 }, 104 { 105 NGM_ETF_COOKIE, 106 NGM_ETF_SET_FILTER, 107 "setfilter", 108 &ng_etf_filter_type, 109 NULL 110 }, 111 { 0 } 112 }; 113 114 /* Netgraph node type descriptor */ 115 static struct ng_type typestruct = { 116 .version = NG_ABI_VERSION, 117 .name = NG_ETF_NODE_TYPE, 118 .constructor = ng_etf_constructor, 119 .rcvmsg = ng_etf_rcvmsg, 120 .shutdown = ng_etf_shutdown, 121 .newhook = ng_etf_newhook, 122 .rcvdata = ng_etf_rcvdata, 123 .disconnect = ng_etf_disconnect, 124 .cmdlist = ng_etf_cmdlist, 125 }; 126 NETGRAPH_INIT(etf, &typestruct); 127 128 /* Information we store for each hook on each node */ 129 struct ETF_hookinfo { 130 hook_p hook; 131 }; 132 133 struct filter { 134 LIST_ENTRY(filter) next; 135 u_int16_t ethertype; /* network order ethertype */ 136 hook_p match_hook; /* Hook to use on a match */ 137 }; 138 139 #define HASHSIZE 16 /* Dont change this without changing HASH() */ 140 #define HASH(et) ((((et)>>12)+((et)>>8)+((et)>>4)+(et)) & 0x0f) 141 LIST_HEAD(filterhead, filter); 142 143 /* Information we store for each node */ 144 struct ETF { 145 struct ETF_hookinfo downstream_hook; 146 struct ETF_hookinfo nomatch_hook; 147 node_p node; /* back pointer to node */ 148 u_int packets_in; /* packets in from downstream */ 149 u_int packets_out; /* packets out towards downstream */ 150 u_int32_t flags; 151 struct filterhead hashtable[HASHSIZE]; 152 }; 153 typedef struct ETF *etf_p; 154 155 static struct filter * 156 ng_etf_findentry(etf_p etfp, u_int16_t ethertype) 157 { 158 struct filterhead *chain = etfp->hashtable + HASH(ethertype); 159 struct filter *fil; 160 161 162 LIST_FOREACH(fil, chain, next) { 163 if (fil->ethertype == ethertype) { 164 return (fil); 165 } 166 } 167 return (NULL); 168 } 169 170 171 /* 172 * Allocate the private data structure. The generic node has already 173 * been created. Link them together. We arrive with a reference to the node 174 * i.e. the reference count is incremented for us already. 175 */ 176 static int 177 ng_etf_constructor(node_p node) 178 { 179 etf_p privdata; 180 int i; 181 182 /* Initialize private descriptor */ 183 MALLOC(privdata, etf_p, sizeof(*privdata), M_NETGRAPH_ETF, 184 M_NOWAIT | M_ZERO); 185 if (privdata == NULL) 186 return (ENOMEM); 187 for (i = 0; i < HASHSIZE; i++) { 188 LIST_INIT((privdata->hashtable + i)); 189 } 190 191 /* Link structs together; this counts as our one reference to node */ 192 NG_NODE_SET_PRIVATE(node, privdata); 193 privdata->node = node; 194 return (0); 195 } 196 197 /* 198 * Give our ok for a hook to be added... 199 * All names are ok. Two names are special. 200 */ 201 static int 202 ng_etf_newhook(node_p node, hook_p hook, const char *name) 203 { 204 const etf_p etfp = NG_NODE_PRIVATE(node); 205 struct ETF_hookinfo *hpriv; 206 207 if (strcmp(name, NG_ETF_HOOK_DOWNSTREAM) == 0) { 208 etfp->downstream_hook.hook = hook; 209 NG_HOOK_SET_PRIVATE(hook, &etfp->downstream_hook); 210 etfp->packets_in = 0; 211 etfp->packets_out = 0; 212 } else if (strcmp(name, NG_ETF_HOOK_NOMATCH) == 0) { 213 etfp->nomatch_hook.hook = hook; 214 NG_HOOK_SET_PRIVATE(hook, &etfp->nomatch_hook); 215 } else { 216 /* 217 * Any other hook name is valid and can 218 * later be associated with a filter rule. 219 */ 220 MALLOC(hpriv, struct ETF_hookinfo *, sizeof(*hpriv), 221 M_NETGRAPH_ETF, M_NOWAIT | M_ZERO); 222 if (hpriv == NULL) { 223 return (ENOMEM); 224 } 225 226 NG_HOOK_SET_PRIVATE(hook, hpriv); 227 hpriv->hook = hook; 228 } 229 return(0); 230 } 231 232 /* 233 * Get a netgraph control message. 234 * We actually recieve a queue item that has a pointer to the message. 235 * If we free the item, the message will be freed too, unless we remove 236 * it from the item using NGI_GET_MSG(); 237 * The return address is also stored in the item, as an ng_ID_t, 238 * accessible as NGI_RETADDR(item); 239 * Check it is one we understand. If needed, send a response. 240 * We could save the address for an async action later, but don't here. 241 * Always free the message. 242 * The response should be in a malloc'd region that the caller can 'free'. 243 * The NG_MKRESPONSE macro does all this for us. 244 * A response is not required. 245 * Theoretically you could respond defferently to old message types if 246 * the cookie in the header didn't match what we consider to be current 247 * (so that old userland programs could continue to work). 248 */ 249 static int 250 ng_etf_rcvmsg(node_p node, item_p item, hook_p lasthook) 251 { 252 const etf_p etfp = NG_NODE_PRIVATE(node); 253 struct ng_mesg *resp = NULL; 254 int error = 0; 255 struct ng_mesg *msg; 256 257 NGI_GET_MSG(item, msg); 258 /* Deal with message according to cookie and command */ 259 switch (msg->header.typecookie) { 260 case NGM_ETF_COOKIE: 261 switch (msg->header.cmd) { 262 case NGM_ETF_GET_STATUS: 263 { 264 struct ng_etfstat *stats; 265 266 NG_MKRESPONSE(resp, msg, sizeof(*stats), M_NOWAIT); 267 if (!resp) { 268 error = ENOMEM; 269 break; 270 } 271 stats = (struct ng_etfstat *) resp->data; 272 stats->packets_in = etfp->packets_in; 273 stats->packets_out = etfp->packets_out; 274 break; 275 } 276 case NGM_ETF_SET_FLAG: 277 if (msg->header.arglen != sizeof(u_int32_t)) { 278 error = EINVAL; 279 break; 280 } 281 etfp->flags = *((u_int32_t *) msg->data); 282 break; 283 case NGM_ETF_SET_FILTER: 284 { 285 struct ng_etffilter *f; 286 struct filter *fil; 287 hook_p hook; 288 289 /* Check message long enough for this command */ 290 if (msg->header.arglen != sizeof(*f)) { 291 error = EINVAL; 292 break; 293 } 294 295 /* Make sure hook referenced exists */ 296 f = (struct ng_etffilter *)msg->data; 297 hook = ng_findhook(node, f->matchhook); 298 if (hook == NULL) { 299 error = ENOENT; 300 break; 301 } 302 303 /* and is not the downstream hook */ 304 if (hook == etfp->downstream_hook.hook) { 305 error = EINVAL; 306 break; 307 } 308 309 /* Check we don't already trap this ethertype */ 310 if (ng_etf_findentry(etfp, 311 htons(f->ethertype))) { 312 error = EEXIST; 313 break; 314 } 315 316 /* 317 * Ok, make the filter and put it in the 318 * hashtable ready for matching. 319 */ 320 MALLOC(fil, struct filter *, sizeof(*fil), 321 M_NETGRAPH_ETF, M_NOWAIT | M_ZERO); 322 if (fil == NULL) { 323 error = ENOMEM; 324 break; 325 } 326 327 fil->match_hook = hook; 328 fil->ethertype = htons(f->ethertype); 329 LIST_INSERT_HEAD( etfp->hashtable 330 + HASH(fil->ethertype), 331 fil, next); 332 } 333 break; 334 default: 335 error = EINVAL; /* unknown command */ 336 break; 337 } 338 break; 339 default: 340 error = EINVAL; /* unknown cookie type */ 341 break; 342 } 343 344 /* Take care of synchronous response, if any */ 345 NG_RESPOND_MSG(error, node, item, resp); 346 /* Free the message and return */ 347 NG_FREE_MSG(msg); 348 return(error); 349 } 350 351 /* 352 * Receive data, and do something with it. 353 * Actually we receive a queue item which holds the data. 354 * If we free the item it will also free the data unless we have previously 355 * disassociated it using the NGI_GET_etf() macro. 356 * Possibly send it out on another link after processing. 357 * Possibly do something different if it comes from different 358 * hooks. The caller will never free m , so if we use up this data 359 * or abort we must free it. 360 * 361 * If we want, we may decide to force this data to be queued and reprocessed 362 * at the netgraph NETISR time. 363 * We would do that by setting the HK_QUEUE flag on our hook. We would do that 364 * in the connect() method. 365 */ 366 static int 367 ng_etf_rcvdata(hook_p hook, item_p item ) 368 { 369 const etf_p etfp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 370 struct ether_header *eh; 371 int error = 0; 372 struct mbuf *m; 373 u_int16_t ethertype; 374 struct filter *fil; 375 376 if (NG_HOOK_PRIVATE(hook) == NULL) { /* Shouldn't happen but.. */ 377 NG_FREE_ITEM(item); 378 } 379 380 /* 381 * Everything not from the downstream hook goes to the 382 * downstream hook. But only if it matches the ethertype 383 * of the source hook. Un matching must go to/from 'nomatch'. 384 */ 385 386 /* Make sure we have an entire header */ 387 NGI_GET_M(item, m); 388 if (m->m_len < sizeof(*eh) ) { 389 m = m_pullup(m, sizeof(*eh)); 390 if (m == NULL) { 391 NG_FREE_ITEM(item); 392 return(EINVAL); 393 } 394 } 395 396 eh = mtod(m, struct ether_header *); 397 ethertype = eh->ether_type; 398 fil = ng_etf_findentry(etfp, ethertype); 399 400 /* 401 * if from downstream, select between a match hook or 402 * the nomatch hook 403 */ 404 if (hook == etfp->downstream_hook.hook) { 405 etfp->packets_in++; 406 if (fil && fil->match_hook) { 407 NG_FWD_NEW_DATA(error, item, fil->match_hook, m); 408 } else { 409 NG_FWD_NEW_DATA(error, item,etfp->nomatch_hook.hook, m); 410 } 411 } else { 412 /* 413 * It must be heading towards the downstream. 414 * Check that it's ethertype matches 415 * the filters for it's input hook. 416 * If it doesn't have one, check it's from nomatch. 417 */ 418 if ((fil && (fil->match_hook != hook)) 419 || ((fil == NULL) && (hook != etfp->nomatch_hook.hook))) { 420 NG_FREE_ITEM(item); 421 NG_FREE_M(m); 422 return (EPROTOTYPE); 423 } 424 NG_FWD_NEW_DATA( error, item, etfp->downstream_hook.hook, m); 425 if (error == 0) { 426 etfp->packets_out++; 427 } 428 } 429 return (error); 430 } 431 432 /* 433 * Do local shutdown processing.. 434 * All our links and the name have already been removed. 435 */ 436 static int 437 ng_etf_shutdown(node_p node) 438 { 439 const etf_p privdata = NG_NODE_PRIVATE(node); 440 441 NG_NODE_SET_PRIVATE(node, NULL); 442 NG_NODE_UNREF(privdata->node); 443 FREE(privdata, M_NETGRAPH_ETF); 444 return (0); 445 } 446 447 /* 448 * Hook disconnection 449 * 450 * For this type, removal of the last link destroys the node 451 */ 452 static int 453 ng_etf_disconnect(hook_p hook) 454 { 455 const etf_p etfp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook)); 456 int i; 457 struct filter *fil1, *fil2; 458 459 /* purge any rules that refer to this filter */ 460 for (i = 0; i < HASHSIZE; i++) { 461 fil1 = LIST_FIRST(&etfp->hashtable[i]); 462 while (fil1 != NULL) { 463 fil2 = LIST_NEXT(fil1, next); 464 if (fil1->match_hook == hook) { 465 LIST_REMOVE(fil1, next); 466 FREE(fil1, M_NETGRAPH_ETF); 467 } 468 fil1 = fil2; 469 } 470 } 471 472 /* If it's not one of the special hooks, then free it */ 473 if (hook == etfp->downstream_hook.hook) { 474 etfp->downstream_hook.hook = NULL; 475 } else if (hook == etfp->nomatch_hook.hook) { 476 etfp->nomatch_hook.hook = NULL; 477 } else { 478 if (NG_HOOK_PRIVATE(hook)) /* Paranoia */ 479 FREE(NG_HOOK_PRIVATE(hook), M_NETGRAPH_ETF); 480 } 481 482 NG_HOOK_SET_PRIVATE(hook, NULL); 483 484 if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0) 485 && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) /* already shutting down? */ 486 ng_rmnode_self(NG_HOOK_NODE(hook)); 487 return (0); 488 } 489 490