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