xref: /openbmc/linux/net/sched/em_meta.c (revision d5cb9783536a41df9f9cba5b0a1d78047ed787f7)
1 /*
2  * net/sched/em_meta.c	Metadata ematch
3  *
4  *		This program is free software; you can redistribute it and/or
5  *		modify it under the terms of the GNU General Public License
6  *		as published by the Free Software Foundation; either version
7  *		2 of the License, or (at your option) any later version.
8  *
9  * Authors:	Thomas Graf <tgraf@suug.ch>
10  *
11  * ==========================================================================
12  *
13  * 	The metadata ematch compares two meta objects where each object
14  * 	represents either a meta value stored in the kernel or a static
15  * 	value provided by userspace. The objects are not provided by
16  * 	userspace itself but rather a definition providing the information
17  * 	to build them. Every object is of a certain type which must be
18  * 	equal to the object it is being compared to.
19  *
20  * 	The definition of a objects conists of the type (meta type), a
21  * 	identifier (meta id) and additional type specific information.
22  * 	The meta id is either TCF_META_TYPE_VALUE for values provided by
23  * 	userspace or a index to the meta operations table consisting of
24  * 	function pointers to type specific meta data collectors returning
25  * 	the value of the requested meta value.
26  *
27  * 	         lvalue                                   rvalue
28  * 	      +-----------+                           +-----------+
29  * 	      | type: INT |                           | type: INT |
30  * 	 def  | id: DEV   |                           | id: VALUE |
31  * 	      | data:     |                           | data: 3   |
32  * 	      +-----------+                           +-----------+
33  * 	            |                                       |
34  * 	            ---> meta_ops[INT][DEV](...)            |
35  *	                      |                             |
36  * 	            -----------                             |
37  * 	            V                                       V
38  * 	      +-----------+                           +-----------+
39  * 	      | type: INT |                           | type: INT |
40  * 	 obj  | id: DEV |                             | id: VALUE |
41  * 	      | data: 2   |<--data got filled out     | data: 3   |
42  * 	      +-----------+                           +-----------+
43  * 	            |                                         |
44  * 	            --------------> 2  equals 3 <--------------
45  *
46  * 	This is a simplified schema, the complexity varies depending
47  * 	on the meta type. Obviously, the length of the data must also
48  * 	be provided for non-numeric types.
49  *
50  * 	Additionaly, type dependant modifiers such as shift operators
51  * 	or mask may be applied to extend the functionaliy. As of now,
52  * 	the variable length type supports shifting the byte string to
53  * 	the right, eating up any number of octets and thus supporting
54  * 	wildcard interface name comparisons such as "ppp%" matching
55  * 	ppp0..9.
56  *
57  * 	NOTE: Certain meta values depend on other subsystems and are
58  * 	      only available if that subsytem is enabled in the kernel.
59  */
60 
61 #include <linux/config.h>
62 #include <linux/module.h>
63 #include <linux/types.h>
64 #include <linux/kernel.h>
65 #include <linux/sched.h>
66 #include <linux/string.h>
67 #include <linux/skbuff.h>
68 #include <linux/random.h>
69 #include <linux/tc_ematch/tc_em_meta.h>
70 #include <net/dst.h>
71 #include <net/route.h>
72 #include <net/pkt_cls.h>
73 #include <net/sock.h>
74 
75 struct meta_obj
76 {
77 	unsigned long		value;
78 	unsigned int		len;
79 };
80 
81 struct meta_value
82 {
83 	struct tcf_meta_val	hdr;
84 	unsigned long		val;
85 	unsigned int		len;
86 };
87 
88 struct meta_match
89 {
90 	struct meta_value	lvalue;
91 	struct meta_value	rvalue;
92 };
93 
94 static inline int meta_id(struct meta_value *v)
95 {
96 	return TCF_META_ID(v->hdr.kind);
97 }
98 
99 static inline int meta_type(struct meta_value *v)
100 {
101 	return TCF_META_TYPE(v->hdr.kind);
102 }
103 
104 #define META_COLLECTOR(FUNC) static void meta_##FUNC(struct sk_buff *skb, \
105 	struct tcf_pkt_info *info, struct meta_value *v, \
106 	struct meta_obj *dst, int *err)
107 
108 /**************************************************************************
109  * System status & misc
110  **************************************************************************/
111 
112 META_COLLECTOR(int_random)
113 {
114 	get_random_bytes(&dst->value, sizeof(dst->value));
115 }
116 
117 static inline unsigned long fixed_loadavg(int load)
118 {
119 	int rnd_load = load + (FIXED_1/200);
120 	int rnd_frac = ((rnd_load & (FIXED_1-1)) * 100) >> FSHIFT;
121 
122 	return ((rnd_load >> FSHIFT) * 100) + rnd_frac;
123 }
124 
125 META_COLLECTOR(int_loadavg_0)
126 {
127 	dst->value = fixed_loadavg(avenrun[0]);
128 }
129 
130 META_COLLECTOR(int_loadavg_1)
131 {
132 	dst->value = fixed_loadavg(avenrun[1]);
133 }
134 
135 META_COLLECTOR(int_loadavg_2)
136 {
137 	dst->value = fixed_loadavg(avenrun[2]);
138 }
139 
140 /**************************************************************************
141  * Device names & indices
142  **************************************************************************/
143 
144 static inline int int_dev(struct net_device *dev, struct meta_obj *dst)
145 {
146 	if (unlikely(dev == NULL))
147 		return -1;
148 
149 	dst->value = dev->ifindex;
150 	return 0;
151 }
152 
153 static inline int var_dev(struct net_device *dev, struct meta_obj *dst)
154 {
155 	if (unlikely(dev == NULL))
156 		return -1;
157 
158 	dst->value = (unsigned long) dev->name;
159 	dst->len = strlen(dev->name);
160 	return 0;
161 }
162 
163 META_COLLECTOR(int_dev)
164 {
165 	*err = int_dev(skb->dev, dst);
166 }
167 
168 META_COLLECTOR(var_dev)
169 {
170 	*err = var_dev(skb->dev, dst);
171 }
172 
173 /**************************************************************************
174  * skb attributes
175  **************************************************************************/
176 
177 META_COLLECTOR(int_priority)
178 {
179 	dst->value = skb->priority;
180 }
181 
182 META_COLLECTOR(int_protocol)
183 {
184 	/* Let userspace take care of the byte ordering */
185 	dst->value = skb->protocol;
186 }
187 
188 META_COLLECTOR(int_pkttype)
189 {
190 	dst->value = skb->pkt_type;
191 }
192 
193 META_COLLECTOR(int_pktlen)
194 {
195 	dst->value = skb->len;
196 }
197 
198 META_COLLECTOR(int_datalen)
199 {
200 	dst->value = skb->data_len;
201 }
202 
203 META_COLLECTOR(int_maclen)
204 {
205 	dst->value = skb->mac_len;
206 }
207 
208 /**************************************************************************
209  * Netfilter
210  **************************************************************************/
211 
212 META_COLLECTOR(int_nfmark)
213 {
214 #ifdef CONFIG_NETFILTER
215 	dst->value = skb->nfmark;
216 #else
217 	dst->value = 0;
218 #endif
219 }
220 
221 /**************************************************************************
222  * Traffic Control
223  **************************************************************************/
224 
225 META_COLLECTOR(int_tcindex)
226 {
227 	dst->value = skb->tc_index;
228 }
229 
230 /**************************************************************************
231  * Routing
232  **************************************************************************/
233 
234 META_COLLECTOR(int_rtclassid)
235 {
236 	if (unlikely(skb->dst == NULL))
237 		*err = -1;
238 	else
239 #ifdef CONFIG_NET_CLS_ROUTE
240 		dst->value = skb->dst->tclassid;
241 #else
242 		dst->value = 0;
243 #endif
244 }
245 
246 META_COLLECTOR(int_rtiif)
247 {
248 	if (unlikely(skb->dst == NULL))
249 		*err = -1;
250 	else
251 		dst->value = ((struct rtable*) skb->dst)->fl.iif;
252 }
253 
254 /**************************************************************************
255  * Socket Attributes
256  **************************************************************************/
257 
258 #define SKIP_NONLOCAL(skb)			\
259 	if (unlikely(skb->sk == NULL)) {	\
260 		*err = -1;			\
261 		return;				\
262 	}
263 
264 META_COLLECTOR(int_sk_family)
265 {
266 	SKIP_NONLOCAL(skb);
267 	dst->value = skb->sk->sk_family;
268 }
269 
270 META_COLLECTOR(int_sk_state)
271 {
272 	SKIP_NONLOCAL(skb);
273 	dst->value = skb->sk->sk_state;
274 }
275 
276 META_COLLECTOR(int_sk_reuse)
277 {
278 	SKIP_NONLOCAL(skb);
279 	dst->value = skb->sk->sk_reuse;
280 }
281 
282 META_COLLECTOR(int_sk_bound_if)
283 {
284 	SKIP_NONLOCAL(skb);
285 	/* No error if bound_dev_if is 0, legal userspace check */
286 	dst->value = skb->sk->sk_bound_dev_if;
287 }
288 
289 META_COLLECTOR(var_sk_bound_if)
290 {
291 	SKIP_NONLOCAL(skb);
292 
293 	 if (skb->sk->sk_bound_dev_if == 0) {
294 		dst->value = (unsigned long) "any";
295 		dst->len = 3;
296 	 } else  {
297 		struct net_device *dev;
298 
299 		dev = dev_get_by_index(skb->sk->sk_bound_dev_if);
300 		*err = var_dev(dev, dst);
301 		if (dev)
302 			dev_put(dev);
303 	 }
304 }
305 
306 META_COLLECTOR(int_sk_refcnt)
307 {
308 	SKIP_NONLOCAL(skb);
309 	dst->value = atomic_read(&skb->sk->sk_refcnt);
310 }
311 
312 META_COLLECTOR(int_sk_rcvbuf)
313 {
314 	SKIP_NONLOCAL(skb);
315 	dst->value = skb->sk->sk_rcvbuf;
316 }
317 
318 META_COLLECTOR(int_sk_shutdown)
319 {
320 	SKIP_NONLOCAL(skb);
321 	dst->value = skb->sk->sk_shutdown;
322 }
323 
324 META_COLLECTOR(int_sk_proto)
325 {
326 	SKIP_NONLOCAL(skb);
327 	dst->value = skb->sk->sk_protocol;
328 }
329 
330 META_COLLECTOR(int_sk_type)
331 {
332 	SKIP_NONLOCAL(skb);
333 	dst->value = skb->sk->sk_type;
334 }
335 
336 META_COLLECTOR(int_sk_rmem_alloc)
337 {
338 	SKIP_NONLOCAL(skb);
339 	dst->value = atomic_read(&skb->sk->sk_rmem_alloc);
340 }
341 
342 META_COLLECTOR(int_sk_wmem_alloc)
343 {
344 	SKIP_NONLOCAL(skb);
345 	dst->value = atomic_read(&skb->sk->sk_wmem_alloc);
346 }
347 
348 META_COLLECTOR(int_sk_omem_alloc)
349 {
350 	SKIP_NONLOCAL(skb);
351 	dst->value = atomic_read(&skb->sk->sk_omem_alloc);
352 }
353 
354 META_COLLECTOR(int_sk_rcv_qlen)
355 {
356 	SKIP_NONLOCAL(skb);
357 	dst->value = skb->sk->sk_receive_queue.qlen;
358 }
359 
360 META_COLLECTOR(int_sk_snd_qlen)
361 {
362 	SKIP_NONLOCAL(skb);
363 	dst->value = skb->sk->sk_write_queue.qlen;
364 }
365 
366 META_COLLECTOR(int_sk_wmem_queued)
367 {
368 	SKIP_NONLOCAL(skb);
369 	dst->value = skb->sk->sk_wmem_queued;
370 }
371 
372 META_COLLECTOR(int_sk_fwd_alloc)
373 {
374 	SKIP_NONLOCAL(skb);
375 	dst->value = skb->sk->sk_forward_alloc;
376 }
377 
378 META_COLLECTOR(int_sk_sndbuf)
379 {
380 	SKIP_NONLOCAL(skb);
381 	dst->value = skb->sk->sk_sndbuf;
382 }
383 
384 META_COLLECTOR(int_sk_alloc)
385 {
386 	SKIP_NONLOCAL(skb);
387 	dst->value = skb->sk->sk_allocation;
388 }
389 
390 META_COLLECTOR(int_sk_route_caps)
391 {
392 	SKIP_NONLOCAL(skb);
393 	dst->value = skb->sk->sk_route_caps;
394 }
395 
396 META_COLLECTOR(int_sk_hash)
397 {
398 	SKIP_NONLOCAL(skb);
399 	dst->value = skb->sk->sk_hash;
400 }
401 
402 META_COLLECTOR(int_sk_lingertime)
403 {
404 	SKIP_NONLOCAL(skb);
405 	dst->value = skb->sk->sk_lingertime / HZ;
406 }
407 
408 META_COLLECTOR(int_sk_err_qlen)
409 {
410 	SKIP_NONLOCAL(skb);
411 	dst->value = skb->sk->sk_error_queue.qlen;
412 }
413 
414 META_COLLECTOR(int_sk_ack_bl)
415 {
416 	SKIP_NONLOCAL(skb);
417 	dst->value = skb->sk->sk_ack_backlog;
418 }
419 
420 META_COLLECTOR(int_sk_max_ack_bl)
421 {
422 	SKIP_NONLOCAL(skb);
423 	dst->value = skb->sk->sk_max_ack_backlog;
424 }
425 
426 META_COLLECTOR(int_sk_prio)
427 {
428 	SKIP_NONLOCAL(skb);
429 	dst->value = skb->sk->sk_priority;
430 }
431 
432 META_COLLECTOR(int_sk_rcvlowat)
433 {
434 	SKIP_NONLOCAL(skb);
435 	dst->value = skb->sk->sk_rcvlowat;
436 }
437 
438 META_COLLECTOR(int_sk_rcvtimeo)
439 {
440 	SKIP_NONLOCAL(skb);
441 	dst->value = skb->sk->sk_rcvtimeo / HZ;
442 }
443 
444 META_COLLECTOR(int_sk_sndtimeo)
445 {
446 	SKIP_NONLOCAL(skb);
447 	dst->value = skb->sk->sk_sndtimeo / HZ;
448 }
449 
450 META_COLLECTOR(int_sk_sendmsg_off)
451 {
452 	SKIP_NONLOCAL(skb);
453 	dst->value = skb->sk->sk_sndmsg_off;
454 }
455 
456 META_COLLECTOR(int_sk_write_pend)
457 {
458 	SKIP_NONLOCAL(skb);
459 	dst->value = skb->sk->sk_write_pending;
460 }
461 
462 /**************************************************************************
463  * Meta value collectors assignment table
464  **************************************************************************/
465 
466 struct meta_ops
467 {
468 	void		(*get)(struct sk_buff *, struct tcf_pkt_info *,
469 			       struct meta_value *, struct meta_obj *, int *);
470 };
471 
472 #define META_ID(name) TCF_META_ID_##name
473 #define META_FUNC(name) { .get = meta_##name }
474 
475 /* Meta value operations table listing all meta value collectors and
476  * assigns them to a type and meta id. */
477 static struct meta_ops __meta_ops[TCF_META_TYPE_MAX+1][TCF_META_ID_MAX+1] = {
478 	[TCF_META_TYPE_VAR] = {
479 		[META_ID(DEV)]			= META_FUNC(var_dev),
480 		[META_ID(SK_BOUND_IF)] 		= META_FUNC(var_sk_bound_if),
481 	},
482 	[TCF_META_TYPE_INT] = {
483 		[META_ID(RANDOM)]		= META_FUNC(int_random),
484 		[META_ID(LOADAVG_0)]		= META_FUNC(int_loadavg_0),
485 		[META_ID(LOADAVG_1)]		= META_FUNC(int_loadavg_1),
486 		[META_ID(LOADAVG_2)]		= META_FUNC(int_loadavg_2),
487 		[META_ID(DEV)]			= META_FUNC(int_dev),
488 		[META_ID(PRIORITY)]		= META_FUNC(int_priority),
489 		[META_ID(PROTOCOL)]		= META_FUNC(int_protocol),
490 		[META_ID(PKTTYPE)]		= META_FUNC(int_pkttype),
491 		[META_ID(PKTLEN)]		= META_FUNC(int_pktlen),
492 		[META_ID(DATALEN)]		= META_FUNC(int_datalen),
493 		[META_ID(MACLEN)]		= META_FUNC(int_maclen),
494 		[META_ID(NFMARK)]		= META_FUNC(int_nfmark),
495 		[META_ID(TCINDEX)]		= META_FUNC(int_tcindex),
496 		[META_ID(RTCLASSID)]		= META_FUNC(int_rtclassid),
497 		[META_ID(RTIIF)]		= META_FUNC(int_rtiif),
498 		[META_ID(SK_FAMILY)]		= META_FUNC(int_sk_family),
499 		[META_ID(SK_STATE)]		= META_FUNC(int_sk_state),
500 		[META_ID(SK_REUSE)]		= META_FUNC(int_sk_reuse),
501 		[META_ID(SK_BOUND_IF)]		= META_FUNC(int_sk_bound_if),
502 		[META_ID(SK_REFCNT)]		= META_FUNC(int_sk_refcnt),
503 		[META_ID(SK_RCVBUF)]		= META_FUNC(int_sk_rcvbuf),
504 		[META_ID(SK_SNDBUF)]		= META_FUNC(int_sk_sndbuf),
505 		[META_ID(SK_SHUTDOWN)]		= META_FUNC(int_sk_shutdown),
506 		[META_ID(SK_PROTO)]		= META_FUNC(int_sk_proto),
507 		[META_ID(SK_TYPE)]		= META_FUNC(int_sk_type),
508 		[META_ID(SK_RMEM_ALLOC)]	= META_FUNC(int_sk_rmem_alloc),
509 		[META_ID(SK_WMEM_ALLOC)]	= META_FUNC(int_sk_wmem_alloc),
510 		[META_ID(SK_OMEM_ALLOC)]	= META_FUNC(int_sk_omem_alloc),
511 		[META_ID(SK_WMEM_QUEUED)]	= META_FUNC(int_sk_wmem_queued),
512 		[META_ID(SK_RCV_QLEN)]		= META_FUNC(int_sk_rcv_qlen),
513 		[META_ID(SK_SND_QLEN)]		= META_FUNC(int_sk_snd_qlen),
514 		[META_ID(SK_ERR_QLEN)]		= META_FUNC(int_sk_err_qlen),
515 		[META_ID(SK_FORWARD_ALLOCS)]	= META_FUNC(int_sk_fwd_alloc),
516 		[META_ID(SK_ALLOCS)]		= META_FUNC(int_sk_alloc),
517 		[META_ID(SK_ROUTE_CAPS)]	= META_FUNC(int_sk_route_caps),
518 		[META_ID(SK_HASH)]		= META_FUNC(int_sk_hash),
519 		[META_ID(SK_LINGERTIME)]	= META_FUNC(int_sk_lingertime),
520 		[META_ID(SK_ACK_BACKLOG)]	= META_FUNC(int_sk_ack_bl),
521 		[META_ID(SK_MAX_ACK_BACKLOG)]	= META_FUNC(int_sk_max_ack_bl),
522 		[META_ID(SK_PRIO)]		= META_FUNC(int_sk_prio),
523 		[META_ID(SK_RCVLOWAT)]		= META_FUNC(int_sk_rcvlowat),
524 		[META_ID(SK_RCVTIMEO)]		= META_FUNC(int_sk_rcvtimeo),
525 		[META_ID(SK_SNDTIMEO)]		= META_FUNC(int_sk_sndtimeo),
526 		[META_ID(SK_SENDMSG_OFF)]	= META_FUNC(int_sk_sendmsg_off),
527 		[META_ID(SK_WRITE_PENDING)]	= META_FUNC(int_sk_write_pend),
528 	}
529 };
530 
531 static inline struct meta_ops * meta_ops(struct meta_value *val)
532 {
533 	return &__meta_ops[meta_type(val)][meta_id(val)];
534 }
535 
536 /**************************************************************************
537  * Type specific operations for TCF_META_TYPE_VAR
538  **************************************************************************/
539 
540 static int meta_var_compare(struct meta_obj *a, struct meta_obj *b)
541 {
542 	int r = a->len - b->len;
543 
544 	if (r == 0)
545 		r = memcmp((void *) a->value, (void *) b->value, a->len);
546 
547 	return r;
548 }
549 
550 static int meta_var_change(struct meta_value *dst, struct rtattr *rta)
551 {
552 	int len = RTA_PAYLOAD(rta);
553 
554 	dst->val = (unsigned long) kmalloc(len, GFP_KERNEL);
555 	if (dst->val == 0UL)
556 		return -ENOMEM;
557 	memcpy((void *) dst->val, RTA_DATA(rta), len);
558 	dst->len = len;
559 	return 0;
560 }
561 
562 static void meta_var_destroy(struct meta_value *v)
563 {
564 	if (v->val)
565 		kfree((void *) v->val);
566 }
567 
568 static void meta_var_apply_extras(struct meta_value *v,
569 				  struct meta_obj *dst)
570 {
571 	int shift = v->hdr.shift;
572 
573 	if (shift && shift < dst->len)
574 		dst->len -= shift;
575 }
576 
577 static int meta_var_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
578 {
579 	if (v->val && v->len)
580 		RTA_PUT(skb, tlv, v->len, (void *) v->val);
581 	return 0;
582 
583 rtattr_failure:
584 	return -1;
585 }
586 
587 /**************************************************************************
588  * Type specific operations for TCF_META_TYPE_INT
589  **************************************************************************/
590 
591 static int meta_int_compare(struct meta_obj *a, struct meta_obj *b)
592 {
593 	/* Let gcc optimize it, the unlikely is not really based on
594 	 * some numbers but jump free code for mismatches seems
595 	 * more logical. */
596 	if (unlikely(a->value == b->value))
597 		return 0;
598 	else if (a->value < b->value)
599 		return -1;
600 	else
601 		return 1;
602 }
603 
604 static int meta_int_change(struct meta_value *dst, struct rtattr *rta)
605 {
606 	if (RTA_PAYLOAD(rta) >= sizeof(unsigned long)) {
607 		dst->val = *(unsigned long *) RTA_DATA(rta);
608 		dst->len = sizeof(unsigned long);
609 	} else if (RTA_PAYLOAD(rta) == sizeof(u32)) {
610 		dst->val = *(u32 *) RTA_DATA(rta);
611 		dst->len = sizeof(u32);
612 	} else
613 		return -EINVAL;
614 
615 	return 0;
616 }
617 
618 static void meta_int_apply_extras(struct meta_value *v,
619 				  struct meta_obj *dst)
620 {
621 	if (v->hdr.shift)
622 		dst->value >>= v->hdr.shift;
623 
624 	if (v->val)
625 		dst->value &= v->val;
626 }
627 
628 static int meta_int_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
629 {
630 	if (v->len == sizeof(unsigned long))
631 		RTA_PUT(skb, tlv, sizeof(unsigned long), &v->val);
632 	else if (v->len == sizeof(u32)) {
633 		u32 d = v->val;
634 		RTA_PUT(skb, tlv, sizeof(d), &d);
635 	}
636 
637 	return 0;
638 
639 rtattr_failure:
640 	return -1;
641 }
642 
643 /**************************************************************************
644  * Type specific operations table
645  **************************************************************************/
646 
647 struct meta_type_ops
648 {
649 	void	(*destroy)(struct meta_value *);
650 	int	(*compare)(struct meta_obj *, struct meta_obj *);
651 	int	(*change)(struct meta_value *, struct rtattr *);
652 	void	(*apply_extras)(struct meta_value *, struct meta_obj *);
653 	int	(*dump)(struct sk_buff *, struct meta_value *, int);
654 };
655 
656 static struct meta_type_ops __meta_type_ops[TCF_META_TYPE_MAX+1] = {
657 	[TCF_META_TYPE_VAR] = {
658 		.destroy = meta_var_destroy,
659 		.compare = meta_var_compare,
660 		.change = meta_var_change,
661 		.apply_extras = meta_var_apply_extras,
662 		.dump = meta_var_dump
663 	},
664 	[TCF_META_TYPE_INT] = {
665 		.compare = meta_int_compare,
666 		.change = meta_int_change,
667 		.apply_extras = meta_int_apply_extras,
668 		.dump = meta_int_dump
669 	}
670 };
671 
672 static inline struct meta_type_ops * meta_type_ops(struct meta_value *v)
673 {
674 	return &__meta_type_ops[meta_type(v)];
675 }
676 
677 /**************************************************************************
678  * Core
679  **************************************************************************/
680 
681 static inline int meta_get(struct sk_buff *skb, struct tcf_pkt_info *info,
682 			   struct meta_value *v, struct meta_obj *dst)
683 {
684 	int err = 0;
685 
686 	if (meta_id(v) == TCF_META_ID_VALUE) {
687 		dst->value = v->val;
688 		dst->len = v->len;
689 		return 0;
690 	}
691 
692 	meta_ops(v)->get(skb, info, v, dst, &err);
693 	if (err < 0)
694 		return err;
695 
696 	if (meta_type_ops(v)->apply_extras)
697 	    meta_type_ops(v)->apply_extras(v, dst);
698 
699 	return 0;
700 }
701 
702 static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m,
703 			 struct tcf_pkt_info *info)
704 {
705 	int r;
706 	struct meta_match *meta = (struct meta_match *) m->data;
707 	struct meta_obj l_value, r_value;
708 
709 	if (meta_get(skb, info, &meta->lvalue, &l_value) < 0 ||
710 	    meta_get(skb, info, &meta->rvalue, &r_value) < 0)
711 		return 0;
712 
713 	r = meta_type_ops(&meta->lvalue)->compare(&l_value, &r_value);
714 
715 	switch (meta->lvalue.hdr.op) {
716 		case TCF_EM_OPND_EQ:
717 			return !r;
718 		case TCF_EM_OPND_LT:
719 			return r < 0;
720 		case TCF_EM_OPND_GT:
721 			return r > 0;
722 	}
723 
724 	return 0;
725 }
726 
727 static inline void meta_delete(struct meta_match *meta)
728 {
729 	struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);
730 
731 	if (ops && ops->destroy) {
732 		ops->destroy(&meta->lvalue);
733 		ops->destroy(&meta->rvalue);
734 	}
735 
736 	kfree(meta);
737 }
738 
739 static inline int meta_change_data(struct meta_value *dst, struct rtattr *rta)
740 {
741 	if (rta) {
742 		if (RTA_PAYLOAD(rta) == 0)
743 			return -EINVAL;
744 
745 		return meta_type_ops(dst)->change(dst, rta);
746 	}
747 
748 	return 0;
749 }
750 
751 static inline int meta_is_supported(struct meta_value *val)
752 {
753 	return (!meta_id(val) || meta_ops(val)->get);
754 }
755 
756 static int em_meta_change(struct tcf_proto *tp, void *data, int len,
757 			  struct tcf_ematch *m)
758 {
759 	int err = -EINVAL;
760 	struct rtattr *tb[TCA_EM_META_MAX];
761 	struct tcf_meta_hdr *hdr;
762 	struct meta_match *meta = NULL;
763 
764 	if (rtattr_parse(tb, TCA_EM_META_MAX, data, len) < 0)
765 		goto errout;
766 
767 	if (tb[TCA_EM_META_HDR-1] == NULL ||
768 	    RTA_PAYLOAD(tb[TCA_EM_META_HDR-1]) < sizeof(*hdr))
769 		goto errout;
770 	hdr = RTA_DATA(tb[TCA_EM_META_HDR-1]);
771 
772 	if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) ||
773 	    TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX ||
774 	    TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX ||
775 	    TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX)
776 		goto errout;
777 
778 	meta = kmalloc(sizeof(*meta), GFP_KERNEL);
779 	if (meta == NULL)
780 		goto errout;
781 	memset(meta, 0, sizeof(*meta));
782 
783 	memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left));
784 	memcpy(&meta->rvalue.hdr, &hdr->right, sizeof(hdr->right));
785 
786 	if (!meta_is_supported(&meta->lvalue) ||
787 	    !meta_is_supported(&meta->rvalue)) {
788 		err = -EOPNOTSUPP;
789 		goto errout;
790 	}
791 
792 	if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE-1]) < 0 ||
793 	    meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE-1]) < 0)
794 		goto errout;
795 
796 	m->datalen = sizeof(*meta);
797 	m->data = (unsigned long) meta;
798 
799 	err = 0;
800 errout:
801 	if (err && meta)
802 		meta_delete(meta);
803 	return err;
804 }
805 
806 static void em_meta_destroy(struct tcf_proto *tp, struct tcf_ematch *m)
807 {
808 	if (m)
809 		meta_delete((struct meta_match *) m->data);
810 }
811 
812 static int em_meta_dump(struct sk_buff *skb, struct tcf_ematch *em)
813 {
814 	struct meta_match *meta = (struct meta_match *) em->data;
815 	struct tcf_meta_hdr hdr;
816 	struct meta_type_ops *ops;
817 
818 	memset(&hdr, 0, sizeof(hdr));
819 	memcpy(&hdr.left, &meta->lvalue.hdr, sizeof(hdr.left));
820 	memcpy(&hdr.right, &meta->rvalue.hdr, sizeof(hdr.right));
821 
822 	RTA_PUT(skb, TCA_EM_META_HDR, sizeof(hdr), &hdr);
823 
824 	ops = meta_type_ops(&meta->lvalue);
825 	if (ops->dump(skb, &meta->lvalue, TCA_EM_META_LVALUE) < 0 ||
826 	    ops->dump(skb, &meta->rvalue, TCA_EM_META_RVALUE) < 0)
827 		goto rtattr_failure;
828 
829 	return 0;
830 
831 rtattr_failure:
832 	return -1;
833 }
834 
835 static struct tcf_ematch_ops em_meta_ops = {
836 	.kind	  = TCF_EM_META,
837 	.change	  = em_meta_change,
838 	.match	  = em_meta_match,
839 	.destroy  = em_meta_destroy,
840 	.dump	  = em_meta_dump,
841 	.owner	  = THIS_MODULE,
842 	.link	  = LIST_HEAD_INIT(em_meta_ops.link)
843 };
844 
845 static int __init init_em_meta(void)
846 {
847 	return tcf_em_register(&em_meta_ops);
848 }
849 
850 static void __exit exit_em_meta(void)
851 {
852 	tcf_em_unregister(&em_meta_ops);
853 }
854 
855 MODULE_LICENSE("GPL");
856 
857 module_init(init_em_meta);
858 module_exit(exit_em_meta);
859