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: releng/12.0/sys/netgraph/ng_etf.c 326272 2017-11-27 15:23:17Z pfg $
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
164 LIST_FOREACH(fil, chain, next) {
165 if (fil->ethertype == ethertype) {
166 return (fil);
167 }
168 }
169 return (NULL);
170 }
171
172
173 /*
174 * Allocate the private data structure. The generic node has already
175 * been created. Link them together. We arrive with a reference to the node
176 * i.e. the reference count is incremented for us already.
177 */
178 static int
179 ng_etf_constructor(node_p node)
180 {
181 etf_p privdata;
182 int i;
183
184 /* Initialize private descriptor */
185 privdata = malloc(sizeof(*privdata), M_NETGRAPH_ETF, M_WAITOK | M_ZERO);
186 for (i = 0; i < HASHSIZE; i++) {
187 LIST_INIT((privdata->hashtable + i));
188 }
189
190 /* Link structs together; this counts as our one reference to node */
191 NG_NODE_SET_PRIVATE(node, privdata);
192 privdata->node = node;
193 return (0);
194 }
195
196 /*
197 * Give our ok for a hook to be added...
198 * All names are ok. Two names are special.
199 */
200 static int
201 ng_etf_newhook(node_p node, hook_p hook, const char *name)
202 {
203 const etf_p etfp = NG_NODE_PRIVATE(node);
204 struct ETF_hookinfo *hpriv;
205
206 if (strcmp(name, NG_ETF_HOOK_DOWNSTREAM) == 0) {
207 etfp->downstream_hook.hook = hook;
208 NG_HOOK_SET_PRIVATE(hook, &etfp->downstream_hook);
209 etfp->packets_in = 0;
210 etfp->packets_out = 0;
211 } else if (strcmp(name, NG_ETF_HOOK_NOMATCH) == 0) {
212 etfp->nomatch_hook.hook = hook;
213 NG_HOOK_SET_PRIVATE(hook, &etfp->nomatch_hook);
214 } else {
215 /*
216 * Any other hook name is valid and can
217 * later be associated with a filter rule.
218 */
219 hpriv = malloc(sizeof(*hpriv),
220 M_NETGRAPH_ETF, M_NOWAIT | M_ZERO);
221 if (hpriv == NULL) {
222 return (ENOMEM);
223 }
224
225 NG_HOOK_SET_PRIVATE(hook, hpriv);
226 hpriv->hook = hook;
227 }
228 return(0);
229 }
230
231 /*
232 * Get a netgraph control message.
233 * We actually receive a queue item that has a pointer to the message.
234 * If we free the item, the message will be freed too, unless we remove
235 * it from the item using NGI_GET_MSG();
236 * The return address is also stored in the item, as an ng_ID_t,
237 * accessible as NGI_RETADDR(item);
238 * Check it is one we understand. If needed, send a response.
239 * We could save the address for an async action later, but don't here.
240 * Always free the message.
241 * The response should be in a malloc'd region that the caller can 'free'.
242 * The NG_MKRESPONSE macro does all this for us.
243 * A response is not required.
244 * Theoretically you could respond defferently to old message types if
245 * the cookie in the header didn't match what we consider to be current
246 * (so that old userland programs could continue to work).
247 */
248 static int
249 ng_etf_rcvmsg(node_p node, item_p item, hook_p lasthook)
250 {
251 const etf_p etfp = NG_NODE_PRIVATE(node);
252 struct ng_mesg *resp = NULL;
253 int error = 0;
254 struct ng_mesg *msg;
255
256 NGI_GET_MSG(item, msg);
257 /* Deal with message according to cookie and command */
258 switch (msg->header.typecookie) {
259 case NGM_ETF_COOKIE:
260 switch (msg->header.cmd) {
261 case NGM_ETF_GET_STATUS:
262 {
263 struct ng_etfstat *stats;
264
265 NG_MKRESPONSE(resp, msg, sizeof(*stats), M_NOWAIT);
266 if (!resp) {
267 error = ENOMEM;
268 break;
269 }
270 stats = (struct ng_etfstat *) resp->data;
271 stats->packets_in = etfp->packets_in;
272 stats->packets_out = etfp->packets_out;
273 break;
274 }
275 case NGM_ETF_SET_FLAG:
276 if (msg->header.arglen != sizeof(u_int32_t)) {
277 error = EINVAL;
278 break;
279 }
280 etfp->flags = *((u_int32_t *) msg->data);
281 break;
282 case NGM_ETF_SET_FILTER:
283 {
284 struct ng_etffilter *f;
285 struct filter *fil;
286 hook_p hook;
287
288 /* Check message long enough for this command */
289 if (msg->header.arglen != sizeof(*f)) {
290 error = EINVAL;
291 break;
292 }
293
294 /* Make sure hook referenced exists */
295 f = (struct ng_etffilter *)msg->data;
296 hook = ng_findhook(node, f->matchhook);
297 if (hook == NULL) {
298 error = ENOENT;
299 break;
300 }
301
302 /* and is not the downstream hook */
303 if (hook == etfp->downstream_hook.hook) {
304 error = EINVAL;
305 break;
306 }
307
308 /* Check we don't already trap this ethertype */
309 if (ng_etf_findentry(etfp,
310 htons(f->ethertype))) {
311 error = EEXIST;
312 break;
313 }
314
315 /*
316 * Ok, make the filter and put it in the
317 * hashtable ready for matching.
318 */
319 fil = malloc(sizeof(*fil),
320 M_NETGRAPH_ETF, M_NOWAIT | M_ZERO);
321 if (fil == NULL) {
322 error = ENOMEM;
323 break;
324 }
325
326 fil->match_hook = hook;
327 fil->ethertype = htons(f->ethertype);
328 LIST_INSERT_HEAD( etfp->hashtable
329 + HASH(fil->ethertype),
330 fil, next);
331 }
332 break;
333 default:
334 error = EINVAL; /* unknown command */
335 break;
336 }
337 break;
338 default:
339 error = EINVAL; /* unknown cookie type */
340 break;
341 }
342
343 /* Take care of synchronous response, if any */
344 NG_RESPOND_MSG(error, node, item, resp);
345 /* Free the message and return */
346 NG_FREE_MSG(msg);
347 return(error);
348 }
349
350 /*
351 * Receive data, and do something with it.
352 * Actually we receive a queue item which holds the data.
353 * If we free the item it will also free the data unless we have previously
354 * disassociated it using the NGI_GET_etf() macro.
355 * Possibly send it out on another link after processing.
356 * Possibly do something different if it comes from different
357 * hooks. The caller will never free m , so if we use up this data
358 * or abort we must free it.
359 *
360 * If we want, we may decide to force this data to be queued and reprocessed
361 * at the netgraph NETISR time.
362 * We would do that by setting the HK_QUEUE flag on our hook. We would do that
363 * in the connect() method.
364 */
365 static int
366 ng_etf_rcvdata(hook_p hook, item_p item )
367 {
368 const etf_p etfp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
369 struct ether_header *eh;
370 int error = 0;
371 struct mbuf *m;
372 u_int16_t ethertype;
373 struct filter *fil;
374
375 if (NG_HOOK_PRIVATE(hook) == NULL) { /* Shouldn't happen but.. */
376 NG_FREE_ITEM(item);
377 }
378
379 /*
380 * Everything not from the downstream hook goes to the
381 * downstream hook. But only if it matches the ethertype
382 * of the source hook. Un matching must go to/from 'nomatch'.
383 */
384
385 /* Make sure we have an entire header */
386 NGI_GET_M(item, m);
387 if (m->m_len < sizeof(*eh) ) {
388 m = m_pullup(m, sizeof(*eh));
389 if (m == NULL) {
390 NG_FREE_ITEM(item);
391 return(EINVAL);
392 }
393 }
394
395 eh = mtod(m, struct ether_header *);
396 ethertype = eh->ether_type;
397 fil = ng_etf_findentry(etfp, ethertype);
398
399 /*
400 * if from downstream, select between a match hook or
401 * the nomatch hook
402 */
403 if (hook == etfp->downstream_hook.hook) {
404 etfp->packets_in++;
405 if (fil && fil->match_hook) {
406 NG_FWD_NEW_DATA(error, item, fil->match_hook, m);
407 } else {
408 NG_FWD_NEW_DATA(error, item,etfp->nomatch_hook.hook, m);
409 }
410 } else {
411 /*
412 * It must be heading towards the downstream.
413 * Check that it's ethertype matches
414 * the filters for it's input hook.
415 * If it doesn't have one, check it's from nomatch.
416 */
417 if ((fil && (fil->match_hook != hook))
418 || ((fil == NULL) && (hook != etfp->nomatch_hook.hook))) {
419 NG_FREE_ITEM(item);
420 NG_FREE_M(m);
421 return (EPROTOTYPE);
422 }
423 NG_FWD_NEW_DATA( error, item, etfp->downstream_hook.hook, m);
424 if (error == 0) {
425 etfp->packets_out++;
426 }
427 }
428 return (error);
429 }
430
431 /*
432 * Do local shutdown processing..
433 * All our links and the name have already been removed.
434 */
435 static int
436 ng_etf_shutdown(node_p node)
437 {
438 const etf_p privdata = NG_NODE_PRIVATE(node);
439
440 NG_NODE_SET_PRIVATE(node, NULL);
441 NG_NODE_UNREF(privdata->node);
442 free(privdata, M_NETGRAPH_ETF);
443 return (0);
444 }
445
446 /*
447 * Hook disconnection
448 *
449 * For this type, removal of the last link destroys the node
450 */
451 static int
452 ng_etf_disconnect(hook_p hook)
453 {
454 const etf_p etfp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
455 int i;
456 struct filter *fil1, *fil2;
457
458 /* purge any rules that refer to this filter */
459 for (i = 0; i < HASHSIZE; i++) {
460 fil1 = LIST_FIRST(&etfp->hashtable[i]);
461 while (fil1 != NULL) {
462 fil2 = LIST_NEXT(fil1, next);
463 if (fil1->match_hook == hook) {
464 LIST_REMOVE(fil1, next);
465 free(fil1, M_NETGRAPH_ETF);
466 }
467 fil1 = fil2;
468 }
469 }
470
471 /* If it's not one of the special hooks, then free it */
472 if (hook == etfp->downstream_hook.hook) {
473 etfp->downstream_hook.hook = NULL;
474 } else if (hook == etfp->nomatch_hook.hook) {
475 etfp->nomatch_hook.hook = NULL;
476 } else {
477 if (NG_HOOK_PRIVATE(hook)) /* Paranoia */
478 free(NG_HOOK_PRIVATE(hook), M_NETGRAPH_ETF);
479 }
480
481 NG_HOOK_SET_PRIVATE(hook, NULL);
482
483 if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
484 && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) /* already shutting down? */
485 ng_rmnode_self(NG_HOOK_NODE(hook));
486 return (0);
487 }
488
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