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