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TOMOYO Linux Cross Reference
Linux/net/sched/em_meta.c

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  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  *      Additionally, type dependent 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 subsystem is enabled in the kernel.
 59  */
 60 
 61 #include <linux/slab.h>
 62 #include <linux/module.h>
 63 #include <linux/types.h>
 64 #include <linux/kernel.h>
 65 #include <linux/sched.h>
 66 #include <linux/sched/loadavg.h>
 67 #include <linux/string.h>
 68 #include <linux/skbuff.h>
 69 #include <linux/random.h>
 70 #include <linux/if_vlan.h>
 71 #include <linux/tc_ematch/tc_em_meta.h>
 72 #include <net/dst.h>
 73 #include <net/route.h>
 74 #include <net/pkt_cls.h>
 75 #include <net/sock.h>
 76 
 77 struct meta_obj {
 78         unsigned long           value;
 79         unsigned int            len;
 80 };
 81 
 82 struct meta_value {
 83         struct tcf_meta_val     hdr;
 84         unsigned long           val;
 85         unsigned int            len;
 86 };
 87 
 88 struct meta_match {
 89         struct meta_value       lvalue;
 90         struct meta_value       rvalue;
 91 };
 92 
 93 static inline int meta_id(struct meta_value *v)
 94 {
 95         return TCF_META_ID(v->hdr.kind);
 96 }
 97 
 98 static inline int meta_type(struct meta_value *v)
 99 {
100         return TCF_META_TYPE(v->hdr.kind);
101 }
102 
103 #define META_COLLECTOR(FUNC) static void meta_##FUNC(struct sk_buff *skb, \
104         struct tcf_pkt_info *info, struct meta_value *v, \
105         struct meta_obj *dst, int *err)
106 
107 /**************************************************************************
108  * System status & misc
109  **************************************************************************/
110 
111 META_COLLECTOR(int_random)
112 {
113         get_random_bytes(&dst->value, sizeof(dst->value));
114 }
115 
116 static inline unsigned long fixed_loadavg(int load)
117 {
118         int rnd_load = load + (FIXED_1/200);
119         int rnd_frac = ((rnd_load & (FIXED_1-1)) * 100) >> FSHIFT;
120 
121         return ((rnd_load >> FSHIFT) * 100) + rnd_frac;
122 }
123 
124 META_COLLECTOR(int_loadavg_0)
125 {
126         dst->value = fixed_loadavg(avenrun[0]);
127 }
128 
129 META_COLLECTOR(int_loadavg_1)
130 {
131         dst->value = fixed_loadavg(avenrun[1]);
132 }
133 
134 META_COLLECTOR(int_loadavg_2)
135 {
136         dst->value = fixed_loadavg(avenrun[2]);
137 }
138 
139 /**************************************************************************
140  * Device names & indices
141  **************************************************************************/
142 
143 static inline int int_dev(struct net_device *dev, struct meta_obj *dst)
144 {
145         if (unlikely(dev == NULL))
146                 return -1;
147 
148         dst->value = dev->ifindex;
149         return 0;
150 }
151 
152 static inline int var_dev(struct net_device *dev, struct meta_obj *dst)
153 {
154         if (unlikely(dev == NULL))
155                 return -1;
156 
157         dst->value = (unsigned long) dev->name;
158         dst->len = strlen(dev->name);
159         return 0;
160 }
161 
162 META_COLLECTOR(int_dev)
163 {
164         *err = int_dev(skb->dev, dst);
165 }
166 
167 META_COLLECTOR(var_dev)
168 {
169         *err = var_dev(skb->dev, dst);
170 }
171 
172 /**************************************************************************
173  * vlan tag
174  **************************************************************************/
175 
176 META_COLLECTOR(int_vlan_tag)
177 {
178         unsigned short tag;
179 
180         if (skb_vlan_tag_present(skb))
181                 dst->value = skb_vlan_tag_get(skb);
182         else if (!__vlan_get_tag(skb, &tag))
183                 dst->value = tag;
184         else
185                 *err = -1;
186 }
187 
188 
189 
190 /**************************************************************************
191  * skb attributes
192  **************************************************************************/
193 
194 META_COLLECTOR(int_priority)
195 {
196         dst->value = skb->priority;
197 }
198 
199 META_COLLECTOR(int_protocol)
200 {
201         /* Let userspace take care of the byte ordering */
202         dst->value = tc_skb_protocol(skb);
203 }
204 
205 META_COLLECTOR(int_pkttype)
206 {
207         dst->value = skb->pkt_type;
208 }
209 
210 META_COLLECTOR(int_pktlen)
211 {
212         dst->value = skb->len;
213 }
214 
215 META_COLLECTOR(int_datalen)
216 {
217         dst->value = skb->data_len;
218 }
219 
220 META_COLLECTOR(int_maclen)
221 {
222         dst->value = skb->mac_len;
223 }
224 
225 META_COLLECTOR(int_rxhash)
226 {
227         dst->value = skb_get_hash(skb);
228 }
229 
230 /**************************************************************************
231  * Netfilter
232  **************************************************************************/
233 
234 META_COLLECTOR(int_mark)
235 {
236         dst->value = skb->mark;
237 }
238 
239 /**************************************************************************
240  * Traffic Control
241  **************************************************************************/
242 
243 META_COLLECTOR(int_tcindex)
244 {
245         dst->value = skb->tc_index;
246 }
247 
248 /**************************************************************************
249  * Routing
250  **************************************************************************/
251 
252 META_COLLECTOR(int_rtclassid)
253 {
254         if (unlikely(skb_dst(skb) == NULL))
255                 *err = -1;
256         else
257 #ifdef CONFIG_IP_ROUTE_CLASSID
258                 dst->value = skb_dst(skb)->tclassid;
259 #else
260                 dst->value = 0;
261 #endif
262 }
263 
264 META_COLLECTOR(int_rtiif)
265 {
266         if (unlikely(skb_rtable(skb) == NULL))
267                 *err = -1;
268         else
269                 dst->value = inet_iif(skb);
270 }
271 
272 /**************************************************************************
273  * Socket Attributes
274  **************************************************************************/
275 
276 #define skip_nonlocal(skb) \
277         (unlikely(skb->sk == NULL))
278 
279 META_COLLECTOR(int_sk_family)
280 {
281         if (skip_nonlocal(skb)) {
282                 *err = -1;
283                 return;
284         }
285         dst->value = skb->sk->sk_family;
286 }
287 
288 META_COLLECTOR(int_sk_state)
289 {
290         if (skip_nonlocal(skb)) {
291                 *err = -1;
292                 return;
293         }
294         dst->value = skb->sk->sk_state;
295 }
296 
297 META_COLLECTOR(int_sk_reuse)
298 {
299         if (skip_nonlocal(skb)) {
300                 *err = -1;
301                 return;
302         }
303         dst->value = skb->sk->sk_reuse;
304 }
305 
306 META_COLLECTOR(int_sk_bound_if)
307 {
308         if (skip_nonlocal(skb)) {
309                 *err = -1;
310                 return;
311         }
312         /* No error if bound_dev_if is 0, legal userspace check */
313         dst->value = skb->sk->sk_bound_dev_if;
314 }
315 
316 META_COLLECTOR(var_sk_bound_if)
317 {
318         if (skip_nonlocal(skb)) {
319                 *err = -1;
320                 return;
321         }
322 
323         if (skb->sk->sk_bound_dev_if == 0) {
324                 dst->value = (unsigned long) "any";
325                 dst->len = 3;
326         } else {
327                 struct net_device *dev;
328 
329                 rcu_read_lock();
330                 dev = dev_get_by_index_rcu(sock_net(skb->sk),
331                                            skb->sk->sk_bound_dev_if);
332                 *err = var_dev(dev, dst);
333                 rcu_read_unlock();
334         }
335 }
336 
337 META_COLLECTOR(int_sk_refcnt)
338 {
339         if (skip_nonlocal(skb)) {
340                 *err = -1;
341                 return;
342         }
343         dst->value = refcount_read(&skb->sk->sk_refcnt);
344 }
345 
346 META_COLLECTOR(int_sk_rcvbuf)
347 {
348         const struct sock *sk = skb_to_full_sk(skb);
349 
350         if (!sk) {
351                 *err = -1;
352                 return;
353         }
354         dst->value = sk->sk_rcvbuf;
355 }
356 
357 META_COLLECTOR(int_sk_shutdown)
358 {
359         const struct sock *sk = skb_to_full_sk(skb);
360 
361         if (!sk) {
362                 *err = -1;
363                 return;
364         }
365         dst->value = sk->sk_shutdown;
366 }
367 
368 META_COLLECTOR(int_sk_proto)
369 {
370         const struct sock *sk = skb_to_full_sk(skb);
371 
372         if (!sk) {
373                 *err = -1;
374                 return;
375         }
376         dst->value = sk->sk_protocol;
377 }
378 
379 META_COLLECTOR(int_sk_type)
380 {
381         const struct sock *sk = skb_to_full_sk(skb);
382 
383         if (!sk) {
384                 *err = -1;
385                 return;
386         }
387         dst->value = sk->sk_type;
388 }
389 
390 META_COLLECTOR(int_sk_rmem_alloc)
391 {
392         const struct sock *sk = skb_to_full_sk(skb);
393 
394         if (!sk) {
395                 *err = -1;
396                 return;
397         }
398         dst->value = sk_rmem_alloc_get(sk);
399 }
400 
401 META_COLLECTOR(int_sk_wmem_alloc)
402 {
403         const struct sock *sk = skb_to_full_sk(skb);
404 
405         if (!sk) {
406                 *err = -1;
407                 return;
408         }
409         dst->value = sk_wmem_alloc_get(sk);
410 }
411 
412 META_COLLECTOR(int_sk_omem_alloc)
413 {
414         const struct sock *sk = skb_to_full_sk(skb);
415 
416         if (!sk) {
417                 *err = -1;
418                 return;
419         }
420         dst->value = atomic_read(&sk->sk_omem_alloc);
421 }
422 
423 META_COLLECTOR(int_sk_rcv_qlen)
424 {
425         const struct sock *sk = skb_to_full_sk(skb);
426 
427         if (!sk) {
428                 *err = -1;
429                 return;
430         }
431         dst->value = sk->sk_receive_queue.qlen;
432 }
433 
434 META_COLLECTOR(int_sk_snd_qlen)
435 {
436         const struct sock *sk = skb_to_full_sk(skb);
437 
438         if (!sk) {
439                 *err = -1;
440                 return;
441         }
442         dst->value = sk->sk_write_queue.qlen;
443 }
444 
445 META_COLLECTOR(int_sk_wmem_queued)
446 {
447         const struct sock *sk = skb_to_full_sk(skb);
448 
449         if (!sk) {
450                 *err = -1;
451                 return;
452         }
453         dst->value = sk->sk_wmem_queued;
454 }
455 
456 META_COLLECTOR(int_sk_fwd_alloc)
457 {
458         const struct sock *sk = skb_to_full_sk(skb);
459 
460         if (!sk) {
461                 *err = -1;
462                 return;
463         }
464         dst->value = sk->sk_forward_alloc;
465 }
466 
467 META_COLLECTOR(int_sk_sndbuf)
468 {
469         const struct sock *sk = skb_to_full_sk(skb);
470 
471         if (!sk) {
472                 *err = -1;
473                 return;
474         }
475         dst->value = sk->sk_sndbuf;
476 }
477 
478 META_COLLECTOR(int_sk_alloc)
479 {
480         const struct sock *sk = skb_to_full_sk(skb);
481 
482         if (!sk) {
483                 *err = -1;
484                 return;
485         }
486         dst->value = (__force int) sk->sk_allocation;
487 }
488 
489 META_COLLECTOR(int_sk_hash)
490 {
491         if (skip_nonlocal(skb)) {
492                 *err = -1;
493                 return;
494         }
495         dst->value = skb->sk->sk_hash;
496 }
497 
498 META_COLLECTOR(int_sk_lingertime)
499 {
500         const struct sock *sk = skb_to_full_sk(skb);
501 
502         if (!sk) {
503                 *err = -1;
504                 return;
505         }
506         dst->value = sk->sk_lingertime / HZ;
507 }
508 
509 META_COLLECTOR(int_sk_err_qlen)
510 {
511         const struct sock *sk = skb_to_full_sk(skb);
512 
513         if (!sk) {
514                 *err = -1;
515                 return;
516         }
517         dst->value = sk->sk_error_queue.qlen;
518 }
519 
520 META_COLLECTOR(int_sk_ack_bl)
521 {
522         const struct sock *sk = skb_to_full_sk(skb);
523 
524         if (!sk) {
525                 *err = -1;
526                 return;
527         }
528         dst->value = sk->sk_ack_backlog;
529 }
530 
531 META_COLLECTOR(int_sk_max_ack_bl)
532 {
533         const struct sock *sk = skb_to_full_sk(skb);
534 
535         if (!sk) {
536                 *err = -1;
537                 return;
538         }
539         dst->value = sk->sk_max_ack_backlog;
540 }
541 
542 META_COLLECTOR(int_sk_prio)
543 {
544         const struct sock *sk = skb_to_full_sk(skb);
545 
546         if (!sk) {
547                 *err = -1;
548                 return;
549         }
550         dst->value = sk->sk_priority;
551 }
552 
553 META_COLLECTOR(int_sk_rcvlowat)
554 {
555         const struct sock *sk = skb_to_full_sk(skb);
556 
557         if (!sk) {
558                 *err = -1;
559                 return;
560         }
561         dst->value = sk->sk_rcvlowat;
562 }
563 
564 META_COLLECTOR(int_sk_rcvtimeo)
565 {
566         const struct sock *sk = skb_to_full_sk(skb);
567 
568         if (!sk) {
569                 *err = -1;
570                 return;
571         }
572         dst->value = sk->sk_rcvtimeo / HZ;
573 }
574 
575 META_COLLECTOR(int_sk_sndtimeo)
576 {
577         const struct sock *sk = skb_to_full_sk(skb);
578 
579         if (!sk) {
580                 *err = -1;
581                 return;
582         }
583         dst->value = sk->sk_sndtimeo / HZ;
584 }
585 
586 META_COLLECTOR(int_sk_sendmsg_off)
587 {
588         const struct sock *sk = skb_to_full_sk(skb);
589 
590         if (!sk) {
591                 *err = -1;
592                 return;
593         }
594         dst->value = sk->sk_frag.offset;
595 }
596 
597 META_COLLECTOR(int_sk_write_pend)
598 {
599         const struct sock *sk = skb_to_full_sk(skb);
600 
601         if (!sk) {
602                 *err = -1;
603                 return;
604         }
605         dst->value = sk->sk_write_pending;
606 }
607 
608 /**************************************************************************
609  * Meta value collectors assignment table
610  **************************************************************************/
611 
612 struct meta_ops {
613         void            (*get)(struct sk_buff *, struct tcf_pkt_info *,
614                                struct meta_value *, struct meta_obj *, int *);
615 };
616 
617 #define META_ID(name) TCF_META_ID_##name
618 #define META_FUNC(name) { .get = meta_##name }
619 
620 /* Meta value operations table listing all meta value collectors and
621  * assigns them to a type and meta id. */
622 static struct meta_ops __meta_ops[TCF_META_TYPE_MAX + 1][TCF_META_ID_MAX + 1] = {
623         [TCF_META_TYPE_VAR] = {
624                 [META_ID(DEV)]                  = META_FUNC(var_dev),
625                 [META_ID(SK_BOUND_IF)]          = META_FUNC(var_sk_bound_if),
626         },
627         [TCF_META_TYPE_INT] = {
628                 [META_ID(RANDOM)]               = META_FUNC(int_random),
629                 [META_ID(LOADAVG_0)]            = META_FUNC(int_loadavg_0),
630                 [META_ID(LOADAVG_1)]            = META_FUNC(int_loadavg_1),
631                 [META_ID(LOADAVG_2)]            = META_FUNC(int_loadavg_2),
632                 [META_ID(DEV)]                  = META_FUNC(int_dev),
633                 [META_ID(PRIORITY)]             = META_FUNC(int_priority),
634                 [META_ID(PROTOCOL)]             = META_FUNC(int_protocol),
635                 [META_ID(PKTTYPE)]              = META_FUNC(int_pkttype),
636                 [META_ID(PKTLEN)]               = META_FUNC(int_pktlen),
637                 [META_ID(DATALEN)]              = META_FUNC(int_datalen),
638                 [META_ID(MACLEN)]               = META_FUNC(int_maclen),
639                 [META_ID(NFMARK)]               = META_FUNC(int_mark),
640                 [META_ID(TCINDEX)]              = META_FUNC(int_tcindex),
641                 [META_ID(RTCLASSID)]            = META_FUNC(int_rtclassid),
642                 [META_ID(RTIIF)]                = META_FUNC(int_rtiif),
643                 [META_ID(SK_FAMILY)]            = META_FUNC(int_sk_family),
644                 [META_ID(SK_STATE)]             = META_FUNC(int_sk_state),
645                 [META_ID(SK_REUSE)]             = META_FUNC(int_sk_reuse),
646                 [META_ID(SK_BOUND_IF)]          = META_FUNC(int_sk_bound_if),
647                 [META_ID(SK_REFCNT)]            = META_FUNC(int_sk_refcnt),
648                 [META_ID(SK_RCVBUF)]            = META_FUNC(int_sk_rcvbuf),
649                 [META_ID(SK_SNDBUF)]            = META_FUNC(int_sk_sndbuf),
650                 [META_ID(SK_SHUTDOWN)]          = META_FUNC(int_sk_shutdown),
651                 [META_ID(SK_PROTO)]             = META_FUNC(int_sk_proto),
652                 [META_ID(SK_TYPE)]              = META_FUNC(int_sk_type),
653                 [META_ID(SK_RMEM_ALLOC)]        = META_FUNC(int_sk_rmem_alloc),
654                 [META_ID(SK_WMEM_ALLOC)]        = META_FUNC(int_sk_wmem_alloc),
655                 [META_ID(SK_OMEM_ALLOC)]        = META_FUNC(int_sk_omem_alloc),
656                 [META_ID(SK_WMEM_QUEUED)]       = META_FUNC(int_sk_wmem_queued),
657                 [META_ID(SK_RCV_QLEN)]          = META_FUNC(int_sk_rcv_qlen),
658                 [META_ID(SK_SND_QLEN)]          = META_FUNC(int_sk_snd_qlen),
659                 [META_ID(SK_ERR_QLEN)]          = META_FUNC(int_sk_err_qlen),
660                 [META_ID(SK_FORWARD_ALLOCS)]    = META_FUNC(int_sk_fwd_alloc),
661                 [META_ID(SK_ALLOCS)]            = META_FUNC(int_sk_alloc),
662                 [META_ID(SK_HASH)]              = META_FUNC(int_sk_hash),
663                 [META_ID(SK_LINGERTIME)]        = META_FUNC(int_sk_lingertime),
664                 [META_ID(SK_ACK_BACKLOG)]       = META_FUNC(int_sk_ack_bl),
665                 [META_ID(SK_MAX_ACK_BACKLOG)]   = META_FUNC(int_sk_max_ack_bl),
666                 [META_ID(SK_PRIO)]              = META_FUNC(int_sk_prio),
667                 [META_ID(SK_RCVLOWAT)]          = META_FUNC(int_sk_rcvlowat),
668                 [META_ID(SK_RCVTIMEO)]          = META_FUNC(int_sk_rcvtimeo),
669                 [META_ID(SK_SNDTIMEO)]          = META_FUNC(int_sk_sndtimeo),
670                 [META_ID(SK_SENDMSG_OFF)]       = META_FUNC(int_sk_sendmsg_off),
671                 [META_ID(SK_WRITE_PENDING)]     = META_FUNC(int_sk_write_pend),
672                 [META_ID(VLAN_TAG)]             = META_FUNC(int_vlan_tag),
673                 [META_ID(RXHASH)]               = META_FUNC(int_rxhash),
674         }
675 };
676 
677 static inline struct meta_ops *meta_ops(struct meta_value *val)
678 {
679         return &__meta_ops[meta_type(val)][meta_id(val)];
680 }
681 
682 /**************************************************************************
683  * Type specific operations for TCF_META_TYPE_VAR
684  **************************************************************************/
685 
686 static int meta_var_compare(struct meta_obj *a, struct meta_obj *b)
687 {
688         int r = a->len - b->len;
689 
690         if (r == 0)
691                 r = memcmp((void *) a->value, (void *) b->value, a->len);
692 
693         return r;
694 }
695 
696 static int meta_var_change(struct meta_value *dst, struct nlattr *nla)
697 {
698         int len = nla_len(nla);
699 
700         dst->val = (unsigned long)kmemdup(nla_data(nla), len, GFP_KERNEL);
701         if (dst->val == 0UL)
702                 return -ENOMEM;
703         dst->len = len;
704         return 0;
705 }
706 
707 static void meta_var_destroy(struct meta_value *v)
708 {
709         kfree((void *) v->val);
710 }
711 
712 static void meta_var_apply_extras(struct meta_value *v,
713                                   struct meta_obj *dst)
714 {
715         int shift = v->hdr.shift;
716 
717         if (shift && shift < dst->len)
718                 dst->len -= shift;
719 }
720 
721 static int meta_var_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
722 {
723         if (v->val && v->len &&
724             nla_put(skb, tlv, v->len, (void *) v->val))
725                 goto nla_put_failure;
726         return 0;
727 
728 nla_put_failure:
729         return -1;
730 }
731 
732 /**************************************************************************
733  * Type specific operations for TCF_META_TYPE_INT
734  **************************************************************************/
735 
736 static int meta_int_compare(struct meta_obj *a, struct meta_obj *b)
737 {
738         /* Let gcc optimize it, the unlikely is not really based on
739          * some numbers but jump free code for mismatches seems
740          * more logical. */
741         if (unlikely(a->value == b->value))
742                 return 0;
743         else if (a->value < b->value)
744                 return -1;
745         else
746                 return 1;
747 }
748 
749 static int meta_int_change(struct meta_value *dst, struct nlattr *nla)
750 {
751         if (nla_len(nla) >= sizeof(unsigned long)) {
752                 dst->val = *(unsigned long *) nla_data(nla);
753                 dst->len = sizeof(unsigned long);
754         } else if (nla_len(nla) == sizeof(u32)) {
755                 dst->val = nla_get_u32(nla);
756                 dst->len = sizeof(u32);
757         } else
758                 return -EINVAL;
759 
760         return 0;
761 }
762 
763 static void meta_int_apply_extras(struct meta_value *v,
764                                   struct meta_obj *dst)
765 {
766         if (v->hdr.shift)
767                 dst->value >>= v->hdr.shift;
768 
769         if (v->val)
770                 dst->value &= v->val;
771 }
772 
773 static int meta_int_dump(struct sk_buff *skb, struct meta_value *v, int tlv)
774 {
775         if (v->len == sizeof(unsigned long)) {
776                 if (nla_put(skb, tlv, sizeof(unsigned long), &v->val))
777                         goto nla_put_failure;
778         } else if (v->len == sizeof(u32)) {
779                 if (nla_put_u32(skb, tlv, v->val))
780                         goto nla_put_failure;
781         }
782 
783         return 0;
784 
785 nla_put_failure:
786         return -1;
787 }
788 
789 /**************************************************************************
790  * Type specific operations table
791  **************************************************************************/
792 
793 struct meta_type_ops {
794         void    (*destroy)(struct meta_value *);
795         int     (*compare)(struct meta_obj *, struct meta_obj *);
796         int     (*change)(struct meta_value *, struct nlattr *);
797         void    (*apply_extras)(struct meta_value *, struct meta_obj *);
798         int     (*dump)(struct sk_buff *, struct meta_value *, int);
799 };
800 
801 static const struct meta_type_ops __meta_type_ops[TCF_META_TYPE_MAX + 1] = {
802         [TCF_META_TYPE_VAR] = {
803                 .destroy = meta_var_destroy,
804                 .compare = meta_var_compare,
805                 .change = meta_var_change,
806                 .apply_extras = meta_var_apply_extras,
807                 .dump = meta_var_dump
808         },
809         [TCF_META_TYPE_INT] = {
810                 .compare = meta_int_compare,
811                 .change = meta_int_change,
812                 .apply_extras = meta_int_apply_extras,
813                 .dump = meta_int_dump
814         }
815 };
816 
817 static inline const struct meta_type_ops *meta_type_ops(struct meta_value *v)
818 {
819         return &__meta_type_ops[meta_type(v)];
820 }
821 
822 /**************************************************************************
823  * Core
824  **************************************************************************/
825 
826 static int meta_get(struct sk_buff *skb, struct tcf_pkt_info *info,
827                     struct meta_value *v, struct meta_obj *dst)
828 {
829         int err = 0;
830 
831         if (meta_id(v) == TCF_META_ID_VALUE) {
832                 dst->value = v->val;
833                 dst->len = v->len;
834                 return 0;
835         }
836 
837         meta_ops(v)->get(skb, info, v, dst, &err);
838         if (err < 0)
839                 return err;
840 
841         if (meta_type_ops(v)->apply_extras)
842                 meta_type_ops(v)->apply_extras(v, dst);
843 
844         return 0;
845 }
846 
847 static int em_meta_match(struct sk_buff *skb, struct tcf_ematch *m,
848                          struct tcf_pkt_info *info)
849 {
850         int r;
851         struct meta_match *meta = (struct meta_match *) m->data;
852         struct meta_obj l_value, r_value;
853 
854         if (meta_get(skb, info, &meta->lvalue, &l_value) < 0 ||
855             meta_get(skb, info, &meta->rvalue, &r_value) < 0)
856                 return 0;
857 
858         r = meta_type_ops(&meta->lvalue)->compare(&l_value, &r_value);
859 
860         switch (meta->lvalue.hdr.op) {
861         case TCF_EM_OPND_EQ:
862                 return !r;
863         case TCF_EM_OPND_LT:
864                 return r < 0;
865         case TCF_EM_OPND_GT:
866                 return r > 0;
867         }
868 
869         return 0;
870 }
871 
872 static void meta_delete(struct meta_match *meta)
873 {
874         if (meta) {
875                 const struct meta_type_ops *ops = meta_type_ops(&meta->lvalue);
876 
877                 if (ops && ops->destroy) {
878                         ops->destroy(&meta->lvalue);
879                         ops->destroy(&meta->rvalue);
880                 }
881         }
882 
883         kfree(meta);
884 }
885 
886 static inline int meta_change_data(struct meta_value *dst, struct nlattr *nla)
887 {
888         if (nla) {
889                 if (nla_len(nla) == 0)
890                         return -EINVAL;
891 
892                 return meta_type_ops(dst)->change(dst, nla);
893         }
894 
895         return 0;
896 }
897 
898 static inline int meta_is_supported(struct meta_value *val)
899 {
900         return !meta_id(val) || meta_ops(val)->get;
901 }
902 
903 static const struct nla_policy meta_policy[TCA_EM_META_MAX + 1] = {
904         [TCA_EM_META_HDR]       = { .len = sizeof(struct tcf_meta_hdr) },
905 };
906 
907 static int em_meta_change(struct net *net, void *data, int len,
908                           struct tcf_ematch *m)
909 {
910         int err;
911         struct nlattr *tb[TCA_EM_META_MAX + 1];
912         struct tcf_meta_hdr *hdr;
913         struct meta_match *meta = NULL;
914 
915         err = nla_parse(tb, TCA_EM_META_MAX, data, len, meta_policy, NULL);
916         if (err < 0)
917                 goto errout;
918 
919         err = -EINVAL;
920         if (tb[TCA_EM_META_HDR] == NULL)
921                 goto errout;
922         hdr = nla_data(tb[TCA_EM_META_HDR]);
923 
924         if (TCF_META_TYPE(hdr->left.kind) != TCF_META_TYPE(hdr->right.kind) ||
925             TCF_META_TYPE(hdr->left.kind) > TCF_META_TYPE_MAX ||
926             TCF_META_ID(hdr->left.kind) > TCF_META_ID_MAX ||
927             TCF_META_ID(hdr->right.kind) > TCF_META_ID_MAX)
928                 goto errout;
929 
930         meta = kzalloc(sizeof(*meta), GFP_KERNEL);
931         if (meta == NULL) {
932                 err = -ENOMEM;
933                 goto errout;
934         }
935 
936         memcpy(&meta->lvalue.hdr, &hdr->left, sizeof(hdr->left));
937         memcpy(&meta->rvalue.hdr, &hdr->right, sizeof(hdr->right));
938 
939         if (!meta_is_supported(&meta->lvalue) ||
940             !meta_is_supported(&meta->rvalue)) {
941                 err = -EOPNOTSUPP;
942                 goto errout;
943         }
944 
945         if (meta_change_data(&meta->lvalue, tb[TCA_EM_META_LVALUE]) < 0 ||
946             meta_change_data(&meta->rvalue, tb[TCA_EM_META_RVALUE]) < 0)
947                 goto errout;
948 
949         m->datalen = sizeof(*meta);
950         m->data = (unsigned long) meta;
951 
952         err = 0;
953 errout:
954         if (err && meta)
955                 meta_delete(meta);
956         return err;
957 }
958 
959 static void em_meta_destroy(struct tcf_ematch *m)
960 {
961         if (m)
962                 meta_delete((struct meta_match *) m->data);
963 }
964 
965 static int em_meta_dump(struct sk_buff *skb, struct tcf_ematch *em)
966 {
967         struct meta_match *meta = (struct meta_match *) em->data;
968         struct tcf_meta_hdr hdr;
969         const struct meta_type_ops *ops;
970 
971         memset(&hdr, 0, sizeof(hdr));
972         memcpy(&hdr.left, &meta->lvalue.hdr, sizeof(hdr.left));
973         memcpy(&hdr.right, &meta->rvalue.hdr, sizeof(hdr.right));
974 
975         if (nla_put(skb, TCA_EM_META_HDR, sizeof(hdr), &hdr))
976                 goto nla_put_failure;
977 
978         ops = meta_type_ops(&meta->lvalue);
979         if (ops->dump(skb, &meta->lvalue, TCA_EM_META_LVALUE) < 0 ||
980             ops->dump(skb, &meta->rvalue, TCA_EM_META_RVALUE) < 0)
981                 goto nla_put_failure;
982 
983         return 0;
984 
985 nla_put_failure:
986         return -1;
987 }
988 
989 static struct tcf_ematch_ops em_meta_ops = {
990         .kind     = TCF_EM_META,
991         .change   = em_meta_change,
992         .match    = em_meta_match,
993         .destroy  = em_meta_destroy,
994         .dump     = em_meta_dump,
995         .owner    = THIS_MODULE,
996         .link     = LIST_HEAD_INIT(em_meta_ops.link)
997 };
998 
999 static int __init init_em_meta(void)
1000 {
1001         return tcf_em_register(&em_meta_ops);
1002 }
1003 
1004 static void __exit exit_em_meta(void)
1005 {
1006         tcf_em_unregister(&em_meta_ops);
1007 }
1008 
1009 MODULE_LICENSE("GPL");
1010 
1011 module_init(init_em_meta);
1012 module_exit(exit_em_meta);
1013 
1014 MODULE_ALIAS_TCF_EMATCH(TCF_EM_META);
1015 

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