FreeBSD/Linux Kernel Cross Reference
sys/netgraph/ng_etf.c
1 /*-
2 * ng_etf.c Ethertype filter
3 *
4 * Copyright (c) 2001, FreeBSD Incorporated
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice unmodified, this list of conditions, and the following
12 * disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 *
29 * Author: Julian Elischer <julian@freebsd.org>
30 *
31 * $FreeBSD$
32 */
33
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 #include <sys/mbuf.h>
38 #include <sys/malloc.h>
39 #include <sys/ctype.h>
40 #include <sys/errno.h>
41 #include <sys/queue.h>
42 #include <sys/syslog.h>
43
44 #include <net/ethernet.h>
45
46 #include <netgraph/ng_message.h>
47 #include <netgraph/ng_parse.h>
48 #include <netgraph/ng_etf.h>
49 #include <netgraph/netgraph.h>
50
51 /* If you do complicated mallocs you may want to do this */
52 /* and use it for your mallocs */
53 #ifdef NG_SEPARATE_MALLOC
54 MALLOC_DEFINE(M_NETGRAPH_ETF, "netgraph_etf", "netgraph etf node ");
55 #else
56 #define M_NETGRAPH_ETF M_NETGRAPH
57 #endif
58
59 /*
60 * This section contains the netgraph method declarations for the
61 * etf node. These methods define the netgraph 'type'.
62 */
63
64 static ng_constructor_t ng_etf_constructor;
65 static ng_rcvmsg_t ng_etf_rcvmsg;
66 static ng_shutdown_t ng_etf_shutdown;
67 static ng_newhook_t ng_etf_newhook;
68 static ng_connect_t ng_etf_connect;
69 static ng_rcvdata_t ng_etf_rcvdata; /* note these are both ng_rcvdata_t */
70 static ng_disconnect_t ng_etf_disconnect;
71
72 /* Parse type for struct ng_etfstat */
73 static const struct ng_parse_struct_field ng_etf_stat_type_fields[]
74 = NG_ETF_STATS_TYPE_INFO;
75 static const struct ng_parse_type ng_etf_stat_type = {
76 &ng_parse_struct_type,
77 &ng_etf_stat_type_fields
78 };
79 /* Parse type for struct ng_setfilter */
80 static const struct ng_parse_struct_field ng_etf_filter_type_fields[]
81 = NG_ETF_FILTER_TYPE_INFO;
82 static const struct ng_parse_type ng_etf_filter_type = {
83 &ng_parse_struct_type,
84 &ng_etf_filter_type_fields
85 };
86
87 /* List of commands and how to convert arguments to/from ASCII */
88 static const struct ng_cmdlist ng_etf_cmdlist[] = {
89 {
90 NGM_ETF_COOKIE,
91 NGM_ETF_GET_STATUS,
92 "getstatus",
93 NULL,
94 &ng_etf_stat_type,
95 },
96 {
97 NGM_ETF_COOKIE,
98 NGM_ETF_SET_FLAG,
99 "setflag",
100 &ng_parse_int32_type,
101 NULL
102 },
103 {
104 NGM_ETF_COOKIE,
105 NGM_ETF_SET_FILTER,
106 "setfilter",
107 &ng_etf_filter_type,
108 NULL
109 },
110 { 0 }
111 };
112
113 /* Netgraph node type descriptor */
114 static struct ng_type typestruct = {
115 NG_ABI_VERSION,
116 NG_ETF_NODE_TYPE,
117 NULL,
118 ng_etf_constructor,
119 ng_etf_rcvmsg,
120 ng_etf_shutdown,
121 ng_etf_newhook,
122 NULL,
123 ng_etf_connect,
124 ng_etf_rcvdata,
125 ng_etf_rcvdata,
126 ng_etf_disconnect,
127 ng_etf_cmdlist
128 };
129 NETGRAPH_INIT(etf, &typestruct);
130
131 /* Information we store for each hook on each node */
132 struct ETF_hookinfo {
133 hook_p hook;
134 };
135
136 struct filter {
137 LIST_ENTRY(filter) next;
138 u_int16_t ethertype; /* network order ethertype */
139 hook_p match_hook; /* Hook to use on a match */
140 };
141
142 #define HASHSIZE 16 /* Dont change this without changing HASH() */
143 #define HASH(et) ((((et)>>12)+((et)>>8)+((et)>>4)+(et)) & 0x0f)
144 LIST_HEAD(filterhead, filter);
145
146 /* Information we store for each node */
147 struct ETF {
148 struct ETF_hookinfo downstream_hook;
149 struct ETF_hookinfo nomatch_hook;
150 node_p node; /* back pointer to node */
151 u_int packets_in; /* packets in from downstream */
152 u_int packets_out; /* packets out towards downstream */
153 u_int32_t flags;
154 struct filterhead hashtable[HASHSIZE];
155 };
156 typedef struct ETF *etf_p;
157
158 static struct filter *
159 ng_etf_findentry(etf_p etfp, u_int16_t ethertype)
160 {
161 struct filterhead *chain = etfp->hashtable + HASH(ethertype);
162 struct filter *fil;
163
164
165 LIST_FOREACH(fil, chain, next) {
166 if (fil->ethertype == ethertype) {
167 return (fil);
168 }
169 }
170 return (NULL);
171 }
172
173
174 /*
175 * Allocate the private data structure. The generic node has already
176 * been created. Link them together. We arrive with a reference to the node
177 * i.e. the reference count is incremented for us already.
178 */
179 static int
180 ng_etf_constructor(node_p *nodep)
181 {
182 etf_p privdata;
183 int error, i;
184
185 /* Initialize private descriptor */
186 MALLOC(privdata, etf_p, sizeof(*privdata), M_NETGRAPH_ETF,
187 M_NOWAIT | M_ZERO);
188 if (privdata == NULL)
189 return (ENOMEM);
190 for (i = 0; i < HASHSIZE; i++) {
191 LIST_INIT((privdata->hashtable + i));
192 }
193
194 /* Call the 'generic' (ie, superclass) node constructor */
195 if ((error = ng_make_node_common(&typestruct, nodep))) {
196 FREE(privdata, M_NETGRAPH);
197 return (error);
198 }
199 /* Link structs together; this counts as our one reference to node */
200 NG_NODE_SET_PRIVATE((*nodep), privdata);
201 privdata->node = *nodep;
202 return (0);
203 }
204
205 /*
206 * Give our ok for a hook to be added...
207 * All names are ok. Two names are special.
208 */
209 static int
210 ng_etf_newhook(node_p node, hook_p hook, const char *name)
211 {
212 const etf_p etfp = NG_NODE_PRIVATE(node);
213 struct ETF_hookinfo *hpriv;
214
215 if (strcmp(name, NG_ETF_HOOK_DOWNSTREAM) == 0) {
216 etfp->downstream_hook.hook = hook;
217 NG_HOOK_SET_PRIVATE(hook, &etfp->downstream_hook);
218 etfp->packets_in = 0;
219 etfp->packets_out = 0;
220 } else if (strcmp(name, NG_ETF_HOOK_NOMATCH) == 0) {
221 etfp->nomatch_hook.hook = hook;
222 NG_HOOK_SET_PRIVATE(hook, &etfp->nomatch_hook);
223 } else {
224 /*
225 * Any other hook name is valid and can
226 * later be associated with a filter rule.
227 */
228 MALLOC(hpriv, struct ETF_hookinfo *, sizeof(*hpriv),
229 M_NETGRAPH_ETF, M_NOWAIT | M_ZERO);
230 if (hpriv == NULL) {
231 return (ENOMEM);
232 }
233
234 NG_HOOK_SET_PRIVATE(hook, hpriv);
235 hpriv->hook = hook;
236 }
237 return(0);
238 }
239
240 /*
241 * Get a netgraph control message.
242 * We actually recieve a queue item that has a pointer to the message.
243 * If we free the item, the message will be freed too, unless we remove
244 * it from the item using NGI_GET_MSG();
245 * The return address is also stored in the item, as an ng_ID_t,
246 * accessible as NGI_RETADDR(item);
247 * Check it is one we understand. If needed, send a response.
248 * We could save the address for an async action later, but don't here.
249 * Always free the message.
250 * The response should be in a malloc'd region that the caller can 'free'.
251 * The NG_MKRESPONSE macro does all this for us.
252 * A response is not required.
253 * Theoretically you could respond defferently to old message types if
254 * the cookie in the header didn't match what we consider to be current
255 * (so that old userland programs could continue to work).
256 */
257 static int
258 ng_etf_rcvmsg(node_p node, struct ng_mesg *msg,
259 const char *retaddr, struct ng_mesg **rptr)
260 {
261 const etf_p etfp = NG_NODE_PRIVATE(node);
262 struct ng_mesg *resp = NULL;
263 int error = 0;
264
265 /* Deal with message according to cookie and command */
266 switch (msg->header.typecookie) {
267 case NGM_ETF_COOKIE:
268 switch (msg->header.cmd) {
269 case NGM_ETF_GET_STATUS:
270 {
271 struct ng_etfstat *stats;
272
273 NG_MKRESPONSE(resp, msg, sizeof(*stats), M_NOWAIT);
274 if (!resp) {
275 error = ENOMEM;
276 break;
277 }
278 stats = (struct ng_etfstat *) resp->data;
279 stats->packets_in = etfp->packets_in;
280 stats->packets_out = etfp->packets_out;
281 break;
282 }
283 case NGM_ETF_SET_FLAG:
284 if (msg->header.arglen != sizeof(u_int32_t)) {
285 error = EINVAL;
286 break;
287 }
288 etfp->flags = *((u_int32_t *) msg->data);
289 break;
290 case NGM_ETF_SET_FILTER:
291 {
292 struct ng_etffilter *f;
293 struct filter *fil;
294 hook_p hook;
295
296 /* Check message long enough for this command */
297 if (msg->header.arglen != sizeof(*f)) {
298 error = EINVAL;
299 break;
300 }
301
302 /* Make sure hook referenced exists */
303 f = (struct ng_etffilter *)msg->data;
304 hook = ng_findhook(node, f->matchhook);
305 if (hook == NULL) {
306 error = ENOENT;
307 break;
308 }
309
310 /* and is not the downstream hook */
311 if (hook == etfp->downstream_hook.hook) {
312 error = EINVAL;
313 break;
314 }
315
316 /* Check we don't already trap this ethertype */
317 if (ng_etf_findentry(etfp,
318 htons(f->ethertype))) {
319 error = EEXIST;
320 break;
321 }
322
323 /*
324 * Ok, make the filter and put it in the
325 * hashtable ready for matching.
326 */
327 MALLOC(fil, struct filter *, sizeof(*fil),
328 M_NETGRAPH_ETF, M_NOWAIT | M_ZERO);
329 if (fil == NULL) {
330 return (ENOMEM);
331 }
332
333 fil->match_hook = hook;
334 fil->ethertype = htons(f->ethertype);
335 LIST_INSERT_HEAD( etfp->hashtable
336 + HASH(fil->ethertype),
337 fil, next);
338 }
339 break;
340 default:
341 error = EINVAL; /* unknown command */
342 break;
343 }
344 break;
345 default:
346 error = EINVAL; /* unknown cookie type */
347 break;
348 }
349
350 /* Take care of synchronous response, if any */
351 NG_RESPOND_MSG(error, node, retaddr, resp, rptr);
352 /* Free the message and return */
353 NG_FREE_MSG(msg);
354 return(error);
355 }
356
357 /*
358 * Receive data, and do something with it.
359 * Actually we receive a queue item which holds the data.
360 * If we free the item it wil also froo the data and metadata unless
361 * we have previously disassociated them using the NGI_GET_etf() macros.
362 * Possibly send it out on another link after processing.
363 * Possibly do something different if it comes from different
364 * hooks. the caller will never free m or meta, so
365 * if we use up this data or abort we must free BOTH of these.
366 *
367 * If we want, we may decide to force this data to be queued and reprocessed
368 * at the netgraph NETISR time.
369 * We would do that by setting the HK_QUEUE flag on our hook. We would do that
370 * in the connect() method.
371 */
372 static int
373 ng_etf_rcvdata(hook_p hook, struct mbuf *m, meta_p meta)
374 {
375 const etf_p etfp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
376 struct ether_header *eh;
377 int error = 0;
378 u_int16_t ethertype;
379 struct filter *fil;
380
381 if (NG_HOOK_PRIVATE(hook) == NULL) { /* Shouldn't happen but.. */
382 NG_FREE_DATA(m, meta);
383 }
384
385 /*
386 * Everything not from the downstream hook goes to the
387 * downstream hook. But only if it matches the ethertype
388 * of the source hook. Un matching must go to/from 'nomatch'.
389 */
390
391 /* Make sure we have an entire header */
392 if (m->m_len < sizeof(*eh) ) {
393 m = m_pullup(m, sizeof(*eh));
394 if (m == NULL) {
395 NG_FREE_META(meta);
396 return(EINVAL);
397 }
398 }
399
400 eh = mtod(m, struct ether_header *);
401 ethertype = eh->ether_type;
402 fil = ng_etf_findentry(etfp, ethertype);
403
404 /*
405 * if from downstream, select between a match hook or
406 * the nomatch hook
407 */
408 if (hook == etfp->downstream_hook.hook) {
409 etfp->packets_in++;
410 if (fil && fil->match_hook) {
411 NG_SEND_DATA(error, fil->match_hook, m, meta);
412 } else {
413 NG_SEND_DATA(error, etfp->nomatch_hook.hook, m, meta);
414 }
415 } else {
416 /*
417 * It must be heading towards the downstream.
418 * Check that it's ethertype matches
419 * the filters for it's input hook.
420 * If it doesn't have one, check it's from nomatch.
421 */
422 if ((fil && (fil->match_hook != hook))
423 || ((fil == NULL) && (hook != etfp->nomatch_hook.hook))) {
424 NG_FREE_DATA(m, meta);
425 return (EPROTOTYPE);
426 }
427 NG_SEND_DATA( error, etfp->downstream_hook.hook, m, meta);
428 if (error == 0) {
429 etfp->packets_out++;
430 }
431 }
432 return (error);
433 }
434
435 /*
436 * Do local shutdown processing..
437 * All our links and the name have already been removed.
438 */
439 static int
440 ng_etf_shutdown(node_p node)
441 {
442 const etf_p privdata = NG_NODE_PRIVATE(node);
443
444 node->flags |= NG_INVALID;
445 ng_cutlinks(node);
446 ng_unname(node);
447 NG_NODE_SET_PRIVATE(node, NULL);
448 NG_NODE_UNREF(privdata->node);
449 FREE(privdata, M_NETGRAPH_ETF);
450 return (0);
451 }
452
453 /*
454 * This is called once we've already connected a new hook to the other node.
455 * It gives us a chance to balk at the last minute.
456 */
457 static int
458 ng_etf_connect(hook_p hook)
459 {
460 return (0);
461 }
462
463 /*
464 * Hook disconnection
465 *
466 * For this type, removal of the last link destroys the node
467 */
468 static int
469 ng_etf_disconnect(hook_p hook)
470 {
471 const etf_p etfp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
472 int i;
473 struct filter *fil;
474
475 /* purge any rules that refer to this filter */
476 for (i = 0; i < HASHSIZE; i++) {
477 LIST_FOREACH(fil, (etfp->hashtable + i), next) {
478 if (fil->match_hook == hook) {
479 LIST_REMOVE(fil, next);
480 }
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(NG_HOOK_NODE(hook));
499 return (0);
500 }
501
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