FreeBSD/Linux Kernel Cross Reference
sys/netgraph/ng_etf.c
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 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_connect_t ng_etf_connect;
71 static ng_rcvdata_t ng_etf_rcvdata; /* note these are both ng_rcvdata_t */
72 static ng_disconnect_t ng_etf_disconnect;
73
74 /* Parse type for struct ng_etfstat */
75 static const struct ng_parse_struct_field ng_etf_stat_type_fields[]
76 = NG_ETF_STATS_TYPE_INFO;
77 static const struct ng_parse_type ng_etf_stat_type = {
78 &ng_parse_struct_type,
79 &ng_etf_stat_type_fields
80 };
81 /* Parse type for struct ng_setfilter */
82 static const struct ng_parse_struct_field ng_etf_filter_type_fields[]
83 = NG_ETF_FILTER_TYPE_INFO;
84 static const struct ng_parse_type ng_etf_filter_type = {
85 &ng_parse_struct_type,
86 &ng_etf_filter_type_fields
87 };
88
89 /* List of commands and how to convert arguments to/from ASCII */
90 static const struct ng_cmdlist ng_etf_cmdlist[] = {
91 {
92 NGM_ETF_COOKIE,
93 NGM_ETF_GET_STATUS,
94 "getstatus",
95 NULL,
96 &ng_etf_stat_type,
97 },
98 {
99 NGM_ETF_COOKIE,
100 NGM_ETF_SET_FLAG,
101 "setflag",
102 &ng_parse_int32_type,
103 NULL
104 },
105 {
106 NGM_ETF_COOKIE,
107 NGM_ETF_SET_FILTER,
108 "setfilter",
109 &ng_etf_filter_type,
110 NULL
111 },
112 { 0 }
113 };
114
115 /* Netgraph node type descriptor */
116 static struct ng_type typestruct = {
117 .version = NG_ABI_VERSION,
118 .name = NG_ETF_NODE_TYPE,
119 .constructor = ng_etf_constructor,
120 .rcvmsg = ng_etf_rcvmsg,
121 .shutdown = ng_etf_shutdown,
122 .newhook = ng_etf_newhook,
123 .connect = ng_etf_connect,
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 MALLOC(privdata, etf_p, sizeof(*privdata), M_NETGRAPH_ETF,
186 M_NOWAIT | M_ZERO);
187 if (privdata == NULL)
188 return (ENOMEM);
189 for (i = 0; i < HASHSIZE; i++) {
190 LIST_INIT((privdata->hashtable + i));
191 }
192
193 /* Link structs together; this counts as our one reference to node */
194 NG_NODE_SET_PRIVATE(node, privdata);
195 privdata->node = node;
196 return (0);
197 }
198
199 /*
200 * Give our ok for a hook to be added...
201 * All names are ok. Two names are special.
202 */
203 static int
204 ng_etf_newhook(node_p node, hook_p hook, const char *name)
205 {
206 const etf_p etfp = NG_NODE_PRIVATE(node);
207 struct ETF_hookinfo *hpriv;
208
209 if (strcmp(name, NG_ETF_HOOK_DOWNSTREAM) == 0) {
210 etfp->downstream_hook.hook = hook;
211 NG_HOOK_SET_PRIVATE(hook, &etfp->downstream_hook);
212 etfp->packets_in = 0;
213 etfp->packets_out = 0;
214 } else if (strcmp(name, NG_ETF_HOOK_NOMATCH) == 0) {
215 etfp->nomatch_hook.hook = hook;
216 NG_HOOK_SET_PRIVATE(hook, &etfp->nomatch_hook);
217 } else {
218 /*
219 * Any other hook name is valid and can
220 * later be associated with a filter rule.
221 */
222 MALLOC(hpriv, struct ETF_hookinfo *, sizeof(*hpriv),
223 M_NETGRAPH_ETF, M_NOWAIT | M_ZERO);
224 if (hpriv == NULL) {
225 return (ENOMEM);
226 }
227
228 NG_HOOK_SET_PRIVATE(hook, hpriv);
229 hpriv->hook = hook;
230 }
231 return(0);
232 }
233
234 /*
235 * Get a netgraph control message.
236 * We actually recieve a queue item that has a pointer to the message.
237 * If we free the item, the message will be freed too, unless we remove
238 * it from the item using NGI_GET_MSG();
239 * The return address is also stored in the item, as an ng_ID_t,
240 * accessible as NGI_RETADDR(item);
241 * Check it is one we understand. If needed, send a response.
242 * We could save the address for an async action later, but don't here.
243 * Always free the message.
244 * The response should be in a malloc'd region that the caller can 'free'.
245 * The NG_MKRESPONSE macro does all this for us.
246 * A response is not required.
247 * Theoretically you could respond defferently to old message types if
248 * the cookie in the header didn't match what we consider to be current
249 * (so that old userland programs could continue to work).
250 */
251 static int
252 ng_etf_rcvmsg(node_p node, item_p item, hook_p lasthook)
253 {
254 const etf_p etfp = NG_NODE_PRIVATE(node);
255 struct ng_mesg *resp = NULL;
256 int error = 0;
257 struct ng_mesg *msg;
258
259 NGI_GET_MSG(item, msg);
260 /* Deal with message according to cookie and command */
261 switch (msg->header.typecookie) {
262 case NGM_ETF_COOKIE:
263 switch (msg->header.cmd) {
264 case NGM_ETF_GET_STATUS:
265 {
266 struct ng_etfstat *stats;
267
268 NG_MKRESPONSE(resp, msg, sizeof(*stats), M_NOWAIT);
269 if (!resp) {
270 error = ENOMEM;
271 break;
272 }
273 stats = (struct ng_etfstat *) resp->data;
274 stats->packets_in = etfp->packets_in;
275 stats->packets_out = etfp->packets_out;
276 break;
277 }
278 case NGM_ETF_SET_FLAG:
279 if (msg->header.arglen != sizeof(u_int32_t)) {
280 error = EINVAL;
281 break;
282 }
283 etfp->flags = *((u_int32_t *) msg->data);
284 break;
285 case NGM_ETF_SET_FILTER:
286 {
287 struct ng_etffilter *f;
288 struct filter *fil;
289 hook_p hook;
290
291 /* Check message long enough for this command */
292 if (msg->header.arglen != sizeof(*f)) {
293 error = EINVAL;
294 break;
295 }
296
297 /* Make sure hook referenced exists */
298 f = (struct ng_etffilter *)msg->data;
299 hook = ng_findhook(node, f->matchhook);
300 if (hook == NULL) {
301 error = ENOENT;
302 break;
303 }
304
305 /* and is not the downstream hook */
306 if (hook == etfp->downstream_hook.hook) {
307 error = EINVAL;
308 break;
309 }
310
311 /* Check we don't already trap this ethertype */
312 if (ng_etf_findentry(etfp,
313 htons(f->ethertype))) {
314 error = EEXIST;
315 break;
316 }
317
318 /*
319 * Ok, make the filter and put it in the
320 * hashtable ready for matching.
321 */
322 MALLOC(fil, struct filter *, sizeof(*fil),
323 M_NETGRAPH_ETF, M_NOWAIT | M_ZERO);
324 if (fil == NULL) {
325 error = ENOMEM;
326 break;
327 }
328
329 fil->match_hook = hook;
330 fil->ethertype = htons(f->ethertype);
331 LIST_INSERT_HEAD( etfp->hashtable
332 + HASH(fil->ethertype),
333 fil, next);
334 }
335 break;
336 default:
337 error = EINVAL; /* unknown command */
338 break;
339 }
340 break;
341 default:
342 error = EINVAL; /* unknown cookie type */
343 break;
344 }
345
346 /* Take care of synchronous response, if any */
347 NG_RESPOND_MSG(error, node, item, resp);
348 /* Free the message and return */
349 NG_FREE_MSG(msg);
350 return(error);
351 }
352
353 /*
354 * Receive data, and do something with it.
355 * Actually we receive a queue item which holds the data.
356 * If we free the item it will also free the data unless we have previously
357 * disassociated it using the NGI_GET_etf() macro.
358 * Possibly send it out on another link after processing.
359 * Possibly do something different if it comes from different
360 * hooks. The caller will never free m , so if we use up this data
361 * or abort we must free it.
362 *
363 * If we want, we may decide to force this data to be queued and reprocessed
364 * at the netgraph NETISR time.
365 * We would do that by setting the HK_QUEUE flag on our hook. We would do that
366 * in the connect() method.
367 */
368 static int
369 ng_etf_rcvdata(hook_p hook, item_p item )
370 {
371 const etf_p etfp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
372 struct ether_header *eh;
373 int error = 0;
374 struct mbuf *m;
375 u_int16_t ethertype;
376 struct filter *fil;
377
378 if (NG_HOOK_PRIVATE(hook) == NULL) { /* Shouldn't happen but.. */
379 NG_FREE_ITEM(item);
380 }
381
382 /*
383 * Everything not from the downstream hook goes to the
384 * downstream hook. But only if it matches the ethertype
385 * of the source hook. Un matching must go to/from 'nomatch'.
386 */
387
388 /* Make sure we have an entire header */
389 NGI_GET_M(item, m);
390 if (m->m_len < sizeof(*eh) ) {
391 m = m_pullup(m, sizeof(*eh));
392 if (m == NULL) {
393 NG_FREE_ITEM(item);
394 return(EINVAL);
395 }
396 }
397
398 eh = mtod(m, struct ether_header *);
399 ethertype = eh->ether_type;
400 fil = ng_etf_findentry(etfp, ethertype);
401
402 /*
403 * if from downstream, select between a match hook or
404 * the nomatch hook
405 */
406 if (hook == etfp->downstream_hook.hook) {
407 etfp->packets_in++;
408 if (fil && fil->match_hook) {
409 NG_FWD_NEW_DATA(error, item, fil->match_hook, m);
410 } else {
411 NG_FWD_NEW_DATA(error, item,etfp->nomatch_hook.hook, m);
412 }
413 } else {
414 /*
415 * It must be heading towards the downstream.
416 * Check that it's ethertype matches
417 * the filters for it's input hook.
418 * If it doesn't have one, check it's from nomatch.
419 */
420 if ((fil && (fil->match_hook != hook))
421 || ((fil == NULL) && (hook != etfp->nomatch_hook.hook))) {
422 NG_FREE_ITEM(item);
423 NG_FREE_M(m);
424 return (EPROTOTYPE);
425 }
426 NG_FWD_NEW_DATA( error, item, etfp->downstream_hook.hook, m);
427 if (error == 0) {
428 etfp->packets_out++;
429 }
430 }
431 return (error);
432 }
433
434 /*
435 * Do local shutdown processing..
436 * All our links and the name have already been removed.
437 */
438 static int
439 ng_etf_shutdown(node_p node)
440 {
441 const etf_p privdata = NG_NODE_PRIVATE(node);
442
443 NG_NODE_SET_PRIVATE(node, NULL);
444 NG_NODE_UNREF(privdata->node);
445 FREE(privdata, M_NETGRAPH_ETF);
446 return (0);
447 }
448
449 /*
450 * This is called once we've already connected a new hook to the other node.
451 * It gives us a chance to balk at the last minute.
452 */
453 static int
454 ng_etf_connect(hook_p hook)
455 {
456 return (0);
457 }
458
459 /*
460 * Hook disconnection
461 *
462 * For this type, removal of the last link destroys the node
463 */
464 static int
465 ng_etf_disconnect(hook_p hook)
466 {
467 const etf_p etfp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
468 int i;
469 struct filter *fil1, *fil2;
470
471 /* purge any rules that refer to this filter */
472 for (i = 0; i < HASHSIZE; i++) {
473 fil1 = LIST_FIRST(&etfp->hashtable[i]);
474 while (fil1 != NULL) {
475 fil2 = LIST_NEXT(fil1, next);
476 if (fil1->match_hook == hook) {
477 LIST_REMOVE(fil1, next);
478 FREE(fil1, M_NETGRAPH_ETF);
479 }
480 fil1 = fil2;
481 }
482 }
483
484 /* If it's not one of the special hooks, then free it */
485 if (hook == etfp->downstream_hook.hook) {
486 etfp->downstream_hook.hook = NULL;
487 } else if (hook == etfp->nomatch_hook.hook) {
488 etfp->nomatch_hook.hook = NULL;
489 } else {
490 if (NG_HOOK_PRIVATE(hook)) /* Paranoia */
491 FREE(NG_HOOK_PRIVATE(hook), M_NETGRAPH_ETF);
492 }
493
494 NG_HOOK_SET_PRIVATE(hook, NULL);
495
496 if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
497 && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) /* already shutting down? */
498 ng_rmnode_self(NG_HOOK_NODE(hook));
499 return (0);
500 }
501
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