xref: /dragonfly/sys/netgraph7/etf/ng_etf.c (revision 926deccb) 
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: src/sys/netgraph/ng_etf.c,v 1.9 2005/03/14 20:49:48 glebius Exp $
34  * $DragonFly: src/sys/netgraph7/ng_etf.c,v 1.2 2008/06/26 23:05:35 dillon Exp $
35  */
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/kernel.h>
40 #include <sys/mbuf.h>
41 #include <sys/malloc.h>
42 #include <sys/ctype.h>
43 #include <sys/errno.h>
44 #include <sys/queue.h>
45 #include <sys/syslog.h>
46 
47 #include <net/ethernet.h>
48 
49 #include <netgraph7/ng_message.h>
50 #include <netgraph7/ng_parse.h>
51 #include "ng_etf.h"
52 #include <netgraph7/netgraph.h>
53 
54 /* If you do complicated mallocs you may want to do this */
55 /* and use it for your mallocs */
56 #ifdef NG_SEPARATE_MALLOC
57 static MALLOC_DEFINE(M_NETGRAPH_ETF, "netgraph_etf", "netgraph etf node ");
58 #else
59 #define M_NETGRAPH_ETF M_NETGRAPH
60 #endif
61 
62 /*
63  * This section contains the netgraph method declarations for the
64  * etf node. These methods define the netgraph 'type'.
65  */
66 
67 static ng_constructor_t	ng_etf_constructor;
68 static ng_rcvmsg_t	ng_etf_rcvmsg;
69 static ng_shutdown_t	ng_etf_shutdown;
70 static ng_newhook_t	ng_etf_newhook;
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 	.rcvdata =	ng_etf_rcvdata,
124 	.disconnect =	ng_etf_disconnect,
125 	.cmdlist =	ng_etf_cmdlist,
126 };
127 NETGRAPH_INIT(etf, &typestruct);
128 
129 /* Information we store for each hook on each node */
130 struct ETF_hookinfo {
131 	hook_p  hook;
132 };
133 
134 struct filter {
135 	LIST_ENTRY(filter) next;
136 	u_int16_t	ethertype;	/* network order ethertype */
137 	hook_p		match_hook;	/* Hook to use on a match */
138 };
139 
140 #define HASHSIZE 16 /* Dont change this without changing HASH() */
141 #define HASH(et) ((((et)>>12)+((et)>>8)+((et)>>4)+(et)) & 0x0f)
142 LIST_HEAD(filterhead, filter);
143 
144 /* Information we store for each node */
145 struct ETF {
146 	struct ETF_hookinfo downstream_hook;
147 	struct ETF_hookinfo nomatch_hook;
148 	node_p		node;		/* back pointer to node */
149 	u_int   	packets_in;	/* packets in from downstream */
150 	u_int   	packets_out;	/* packets out towards downstream */
151 	u_int32_t	flags;
152 	struct filterhead hashtable[HASHSIZE];
153 };
154 typedef struct ETF *etf_p;
155 
156 static struct filter *
157 ng_etf_findentry(etf_p etfp, u_int16_t ethertype)
158 {
159 	struct filterhead *chain = etfp->hashtable + HASH(ethertype);
160 	struct filter *fil;
161 
162 
163 	LIST_FOREACH(fil, chain, next) {
164 		if (fil->ethertype == ethertype) {
165 			return (fil);
166 		}
167 	}
168 	return (NULL);
169 }
170 
171 
172 /*
173  * Allocate the private data structure. The generic node has already
174  * been created. Link them together. We arrive with a reference to the node
175  * i.e. the reference count is incremented for us already.
176  */
177 static int
178 ng_etf_constructor(node_p node)
179 {
180 	etf_p privdata;
181 	int i;
182 
183 	/* Initialize private descriptor */
184 	privdata = kmalloc(sizeof(*privdata), M_NETGRAPH_ETF,
185 			   M_WAITOK | M_NULLOK | M_ZERO);
186 	if (privdata == NULL)
187 		return (ENOMEM);
188 	for (i = 0; i < HASHSIZE; i++) {
189 		LIST_INIT((privdata->hashtable + i));
190 	}
191 
192 	/* Link structs together; this counts as our one reference to node */
193 	NG_NODE_SET_PRIVATE(node, privdata);
194 	privdata->node = node;
195 	return (0);
196 }
197 
198 /*
199  * Give our ok for a hook to be added...
200  * All names are ok. Two names are special.
201  */
202 static int
203 ng_etf_newhook(node_p node, hook_p hook, const char *name)
204 {
205 	const etf_p etfp = NG_NODE_PRIVATE(node);
206 	struct ETF_hookinfo *hpriv;
207 
208 	if (strcmp(name, NG_ETF_HOOK_DOWNSTREAM) == 0) {
209 		etfp->downstream_hook.hook = hook;
210 		NG_HOOK_SET_PRIVATE(hook, &etfp->downstream_hook);
211 		etfp->packets_in = 0;
212 		etfp->packets_out = 0;
213 	} else if (strcmp(name, NG_ETF_HOOK_NOMATCH) == 0) {
214 		etfp->nomatch_hook.hook = hook;
215 		NG_HOOK_SET_PRIVATE(hook, &etfp->nomatch_hook);
216 	} else {
217 		/*
218 		 * Any other hook name is valid and can
219 		 * later be associated with a filter rule.
220 		 */
221 		hpriv = kmalloc(sizeof(*hpriv), M_NETGRAPH_ETF,
222 				M_WAITOK | M_NULLOK | M_ZERO);
223 		if (hpriv == NULL) {
224 			return (ENOMEM);
225 		}
226 
227 		NG_HOOK_SET_PRIVATE(hook, hpriv);
228 		hpriv->hook = hook;
229 	}
230 	return(0);
231 }
232 
233 /*
234  * Get a netgraph control message.
235  * We actually recieve a queue item that has a pointer to the message.
236  * If we free the item, the message will be freed too, unless we remove
237  * it from the item using NGI_GET_MSG();
238  * The return address is also stored in the item, as an ng_ID_t,
239  * accessible as NGI_RETADDR(item);
240  * Check it is one we understand. If needed, send a response.
241  * We could save the address for an async action later, but don't here.
242  * Always free the message.
243  * The response should be in a malloc'd region that the caller can 'free'.
244  * The NG_MKRESPONSE macro does all this for us.
245  * A response is not required.
246  * Theoretically you could respond defferently to old message types if
247  * the cookie in the header didn't match what we consider to be current
248  * (so that old userland programs could continue to work).
249  */
250 static int
251 ng_etf_rcvmsg(node_p node, item_p item, hook_p lasthook)
252 {
253 	const etf_p etfp = NG_NODE_PRIVATE(node);
254 	struct ng_mesg *resp = NULL;
255 	int error = 0;
256 	struct ng_mesg *msg;
257 
258 	NGI_GET_MSG(item, msg);
259 	/* Deal with message according to cookie and command */
260 	switch (msg->header.typecookie) {
261 	case NGM_ETF_COOKIE:
262 		switch (msg->header.cmd) {
263 		case NGM_ETF_GET_STATUS:
264 		    {
265 			struct ng_etfstat *stats;
266 
267 			NG_MKRESPONSE(resp, msg, sizeof(*stats), M_WAITOK | M_NULLOK);
268 			if (!resp) {
269 				error = ENOMEM;
270 				break;
271 			}
272 			stats = (struct ng_etfstat *) resp->data;
273 			stats->packets_in = etfp->packets_in;
274 			stats->packets_out = etfp->packets_out;
275 			break;
276 		    }
277 		case NGM_ETF_SET_FLAG:
278 			if (msg->header.arglen != sizeof(u_int32_t)) {
279 				error = EINVAL;
280 				break;
281 			}
282 			etfp->flags = *((u_int32_t *) msg->data);
283 			break;
284 		case NGM_ETF_SET_FILTER:
285 			{
286 				struct ng_etffilter *f;
287 				struct filter *fil;
288 				hook_p  hook;
289 
290 				/* Check message long enough for this command */
291 				if (msg->header.arglen != sizeof(*f)) {
292 					error = EINVAL;
293 					break;
294 				}
295 
296 				/* Make sure hook referenced exists */
297 				f = (struct ng_etffilter *)msg->data;
298 				hook = ng_findhook(node, f->matchhook);
299 				if (hook == NULL) {
300 					error = ENOENT;
301 					break;
302 				}
303 
304 				/* and is not the downstream hook */
305 				if (hook == etfp->downstream_hook.hook) {
306 					error = EINVAL;
307 					break;
308 				}
309 
310 				/* Check we don't already trap this ethertype */
311 				if (ng_etf_findentry(etfp,
312 						htons(f->ethertype))) {
313 					error = EEXIST;
314 					break;
315 				}
316 
317 				/*
318 				 * Ok, make the filter and put it in the
319 				 * hashtable ready for matching.
320 				 */
321 				fil = kmalloc(sizeof(*fil), M_NETGRAPH_ETF,
322 					      M_WAITOK | M_NULLOK | M_ZERO);
323 				if (fil == NULL) {
324 					error = ENOMEM;
325 					break;
326 				}
327 
328 				fil->match_hook = hook;
329 				fil->ethertype = htons(f->ethertype);
330 				LIST_INSERT_HEAD( etfp->hashtable
331 					+ HASH(fil->ethertype),
332 						fil, next);
333 			}
334 			break;
335 		default:
336 			error = EINVAL;		/* unknown command */
337 			break;
338 		}
339 		break;
340 	default:
341 		error = EINVAL;			/* unknown cookie type */
342 		break;
343 	}
344 
345 	/* Take care of synchronous response, if any */
346 	NG_RESPOND_MSG(error, node, item, resp);
347 	/* Free the message and return */
348 	NG_FREE_MSG(msg);
349 	return(error);
350 }
351 
352 /*
353  * Receive data, and do something with it.
354  * Actually we receive a queue item which holds the data.
355  * If we free the item it will also free the data unless we have previously
356  * disassociated it using the NGI_GET_etf() macro.
357  * Possibly send it out on another link after processing.
358  * Possibly do something different if it comes from different
359  * hooks. The caller will never free m , so if we use up this data
360  * or abort we must free it.
361  *
362  * If we want, we may decide to force this data to be queued and reprocessed
363  * at the netgraph NETISR time.
364  * We would do that by setting the HK_QUEUE flag on our hook. We would do that
365  * in the connect() method.
366  */
367 static int
368 ng_etf_rcvdata(hook_p hook, item_p item )
369 {
370 	const etf_p etfp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
371 	struct ether_header *eh;
372 	int error = 0;
373 	struct mbuf *m;
374 	u_int16_t ethertype;
375 	struct filter *fil;
376 
377 	if (NG_HOOK_PRIVATE(hook) == NULL) { /* Shouldn't happen but.. */
378 		NG_FREE_ITEM(item);
379 	}
380 
381 	/*
382 	 * Everything not from the downstream hook goes to the
383 	 * downstream hook. But only if it matches the ethertype
384 	 * of the source hook. Un matching must go to/from 'nomatch'.
385 	 */
386 
387 	/* Make sure we have an entire header */
388 	NGI_GET_M(item, m);
389 	if (m->m_len < sizeof(*eh) ) {
390 		m = m_pullup(m, sizeof(*eh));
391 		if (m == NULL) {
392 			NG_FREE_ITEM(item);
393 			return(EINVAL);
394 		}
395 	}
396 
397 	eh = mtod(m, struct ether_header *);
398 	ethertype = eh->ether_type;
399 	fil = ng_etf_findentry(etfp, ethertype);
400 
401 	/*
402 	 * if from downstream, select between a match hook or
403 	 * the nomatch hook
404 	 */
405 	if (hook == etfp->downstream_hook.hook) {
406 		etfp->packets_in++;
407 		if (fil && fil->match_hook) {
408 			NG_FWD_NEW_DATA(error, item, fil->match_hook, m);
409 		} else {
410 			NG_FWD_NEW_DATA(error, item,etfp->nomatch_hook.hook, m);
411 		}
412 	} else {
413 		/*
414 		 * It must be heading towards the downstream.
415 		 * Check that it's ethertype matches
416 		 * the filters for it's input hook.
417 		 * If it doesn't have one, check it's from nomatch.
418 		 */
419 		if ((fil && (fil->match_hook != hook))
420 		|| ((fil == NULL) && (hook != etfp->nomatch_hook.hook))) {
421 			NG_FREE_ITEM(item);
422 			NG_FREE_M(m);
423 			return (EPROTOTYPE);
424 		}
425 		NG_FWD_NEW_DATA( error, item, etfp->downstream_hook.hook, m);
426 		if (error == 0) {
427 			etfp->packets_out++;
428 		}
429 	}
430 	return (error);
431 }
432 
433 /*
434  * Do local shutdown processing..
435  * All our links and the name have already been removed.
436  */
437 static int
438 ng_etf_shutdown(node_p node)
439 {
440 	const etf_p privdata = NG_NODE_PRIVATE(node);
441 
442 	NG_NODE_SET_PRIVATE(node, NULL);
443 	NG_NODE_UNREF(privdata->node);
444 	kfree(privdata, M_NETGRAPH_ETF);
445 	return (0);
446 }
447 
448 /*
449  * Hook disconnection
450  *
451  * For this type, removal of the last link destroys the node
452  */
453 static int
454 ng_etf_disconnect(hook_p hook)
455 {
456 	const etf_p etfp = NG_NODE_PRIVATE(NG_HOOK_NODE(hook));
457 	int i;
458 	struct filter *fil1, *fil2;
459 
460 	/* purge any rules that refer to this filter */
461 	for (i = 0; i < HASHSIZE; i++) {
462 		fil1 = LIST_FIRST(&etfp->hashtable[i]);
463 		while (fil1 != NULL) {
464 			fil2 = LIST_NEXT(fil1, next);
465 			if (fil1->match_hook == hook) {
466 				LIST_REMOVE(fil1, next);
467 				kfree(fil1, M_NETGRAPH_ETF);
468 			}
469 			fil1 = fil2;
470 		}
471 	}
472 
473 	/* If it's not one of the special hooks, then free it */
474 	if (hook == etfp->downstream_hook.hook) {
475 		etfp->downstream_hook.hook = NULL;
476 	} else if (hook == etfp->nomatch_hook.hook) {
477 		etfp->nomatch_hook.hook = NULL;
478 	} else {
479 		if (NG_HOOK_PRIVATE(hook)) /* Paranoia */
480 			kfree(NG_HOOK_PRIVATE(hook), M_NETGRAPH_ETF);
481 	}
482 
483 	NG_HOOK_SET_PRIVATE(hook, NULL);
484 
485 	if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
486 	&& (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) /* already shutting down? */
487 		ng_rmnode_self(NG_HOOK_NODE(hook));
488 	return (0);
489 }
490 
491