cls_tcindex.c 11.7 KB
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507
/*
 * net/sched/cls_tcindex.c	Packet classifier for skb->tc_index
 *
 * Written 1998,1999 by Werner Almesberger, EPFL ICA
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <net/act_api.h>
#include <net/netlink.h>
#include <net/pkt_cls.h>

/*
 * Passing parameters to the root seems to be done more awkwardly than really
 * necessary. At least, u32 doesn't seem to use such dirty hacks. To be
 * verified. FIXME.
 */

#define PERFECT_HASH_THRESHOLD	64	/* use perfect hash if not bigger */
#define DEFAULT_HASH_SIZE	64	/* optimized for diffserv */


#define	PRIV(tp)	((struct tcindex_data *) (tp)->root)


struct tcindex_filter_result {
	struct tcf_exts		exts;
	struct tcf_result	res;
};

struct tcindex_filter {
	u16 key;
	struct tcindex_filter_result result;
	struct tcindex_filter *next;
};


struct tcindex_data {
	struct tcindex_filter_result *perfect; /* perfect hash; NULL if none */
	struct tcindex_filter **h; /* imperfect hash; only used if !perfect;
				      NULL if unused */
	u16 mask;		/* AND key with mask */
	int shift;		/* shift ANDed key to the right */
	int hash;		/* hash table size; 0 if undefined */
	int alloc_hash;		/* allocated size */
	int fall_through;	/* 0: only classify if explicit match */
};

static const struct tcf_ext_map tcindex_ext_map = {
	.police = TCA_TCINDEX_POLICE,
	.action = TCA_TCINDEX_ACT
};

static inline int
tcindex_filter_is_set(struct tcindex_filter_result *r)
{
	return tcf_exts_is_predicative(&r->exts) || r->res.classid;
}

static struct tcindex_filter_result *
tcindex_lookup(struct tcindex_data *p, u16 key)
{
	struct tcindex_filter *f;

	if (p->perfect)
		return tcindex_filter_is_set(p->perfect + key) ?
			p->perfect + key : NULL;
	else if (p->h) {
		for (f = p->h[key % p->hash]; f; f = f->next)
			if (f->key == key)
				return &f->result;
	}

	return NULL;
}


static int tcindex_classify(struct sk_buff *skb, struct tcf_proto *tp,
			    struct tcf_result *res)
{
	struct tcindex_data *p = PRIV(tp);
	struct tcindex_filter_result *f;
	int key = (skb->tc_index & p->mask) >> p->shift;

	pr_debug("tcindex_classify(skb %p,tp %p,res %p),p %p\n",
		 skb, tp, res, p);

	f = tcindex_lookup(p, key);
	if (!f) {
		if (!p->fall_through)
			return -1;
		res->classid = TC_H_MAKE(TC_H_MAJ(tp->q->handle), key);
		res->class = 0;
		pr_debug("alg 0x%x\n", res->classid);
		return 0;
	}
	*res = f->res;
	pr_debug("map 0x%x\n", res->classid);

	return tcf_exts_exec(skb, &f->exts, res);
}


static unsigned long tcindex_get(struct tcf_proto *tp, u32 handle)
{
	struct tcindex_data *p = PRIV(tp);
	struct tcindex_filter_result *r;

	pr_debug("tcindex_get(tp %p,handle 0x%08x)\n", tp, handle);
	if (p->perfect && handle >= p->alloc_hash)
		return 0;
	r = tcindex_lookup(p, handle);
	return r && tcindex_filter_is_set(r) ? (unsigned long) r : 0UL;
}


static void tcindex_put(struct tcf_proto *tp, unsigned long f)
{
	pr_debug("tcindex_put(tp %p,f 0x%lx)\n", tp, f);
}


static int tcindex_init(struct tcf_proto *tp)
{
	struct tcindex_data *p;

	pr_debug("tcindex_init(tp %p)\n", tp);
	p = kzalloc(sizeof(struct tcindex_data), GFP_KERNEL);
	if (!p)
		return -ENOMEM;

	p->mask = 0xffff;
	p->hash = DEFAULT_HASH_SIZE;
	p->fall_through = 1;

	tp->root = p;
	return 0;
}


static int
__tcindex_delete(struct tcf_proto *tp, unsigned long arg, int lock)
{
	struct tcindex_data *p = PRIV(tp);
	struct tcindex_filter_result *r = (struct tcindex_filter_result *) arg;
	struct tcindex_filter *f = NULL;

	pr_debug("tcindex_delete(tp %p,arg 0x%lx),p %p,f %p\n", tp, arg, p, f);
	if (p->perfect) {
		if (!r->res.class)
			return -ENOENT;
	} else {
		int i;
		struct tcindex_filter **walk = NULL;

		for (i = 0; i < p->hash; i++)
			for (walk = p->h+i; *walk; walk = &(*walk)->next)
				if (&(*walk)->result == r)
					goto found;
		return -ENOENT;

found:
		f = *walk;
		if (lock)
			tcf_tree_lock(tp);
		*walk = f->next;
		if (lock)
			tcf_tree_unlock(tp);
	}
	tcf_unbind_filter(tp, &r->res);
	tcf_exts_destroy(tp, &r->exts);
	kfree(f);
	return 0;
}

static int tcindex_delete(struct tcf_proto *tp, unsigned long arg)
{
	return __tcindex_delete(tp, arg, 1);
}

static inline int
valid_perfect_hash(struct tcindex_data *p)
{
	return  p->hash > (p->mask >> p->shift);
}

static const struct nla_policy tcindex_policy[TCA_TCINDEX_MAX + 1] = {
	[TCA_TCINDEX_HASH]		= { .type = NLA_U32 },
	[TCA_TCINDEX_MASK]		= { .type = NLA_U16 },
	[TCA_TCINDEX_SHIFT]		= { .type = NLA_U32 },
	[TCA_TCINDEX_FALL_THROUGH]	= { .type = NLA_U32 },
	[TCA_TCINDEX_CLASSID]		= { .type = NLA_U32 },
};

static int
tcindex_set_parms(struct tcf_proto *tp, unsigned long base, u32 handle,
		  struct tcindex_data *p, struct tcindex_filter_result *r,
		  struct nlattr **tb, struct nlattr *est)
{
	int err, balloc = 0;
	struct tcindex_filter_result new_filter_result, *old_r = r;
	struct tcindex_filter_result cr;
	struct tcindex_data cp;
	struct tcindex_filter *f = NULL; /* make gcc behave */
	struct tcf_exts e;

	err = tcf_exts_validate(tp, tb, est, &e, &tcindex_ext_map);
	if (err < 0)
		return err;

	memcpy(&cp, p, sizeof(cp));
	memset(&new_filter_result, 0, sizeof(new_filter_result));

	if (old_r)
		memcpy(&cr, r, sizeof(cr));
	else
		memset(&cr, 0, sizeof(cr));

	if (tb[TCA_TCINDEX_HASH])
		cp.hash = nla_get_u32(tb[TCA_TCINDEX_HASH]);

	if (tb[TCA_TCINDEX_MASK])
		cp.mask = nla_get_u16(tb[TCA_TCINDEX_MASK]);

	if (tb[TCA_TCINDEX_SHIFT])
		cp.shift = nla_get_u32(tb[TCA_TCINDEX_SHIFT]);

	err = -EBUSY;
	/* Hash already allocated, make sure that we still meet the
	 * requirements for the allocated hash.
	 */
	if (cp.perfect) {
		if (!valid_perfect_hash(&cp) ||
		    cp.hash > cp.alloc_hash)
			goto errout;
	} else if (cp.h && cp.hash != cp.alloc_hash)
		goto errout;

	err = -EINVAL;
	if (tb[TCA_TCINDEX_FALL_THROUGH])
		cp.fall_through = nla_get_u32(tb[TCA_TCINDEX_FALL_THROUGH]);

	if (!cp.hash) {
		/* Hash not specified, use perfect hash if the upper limit
		 * of the hashing index is below the threshold.
		 */
		if ((cp.mask >> cp.shift) < PERFECT_HASH_THRESHOLD)
			cp.hash = (cp.mask >> cp.shift)+1;
		else
			cp.hash = DEFAULT_HASH_SIZE;
	}

	if (!cp.perfect && !cp.h)
		cp.alloc_hash = cp.hash;

	/* Note: this could be as restrictive as if (handle & ~(mask >> shift))
	 * but then, we'd fail handles that may become valid after some future
	 * mask change. While this is extremely unlikely to ever matter,
	 * the check below is safer (and also more backwards-compatible).
	 */
	if (cp.perfect || valid_perfect_hash(&cp))
		if (handle >= cp.alloc_hash)
			goto errout;


	err = -ENOMEM;
	if (!cp.perfect && !cp.h) {
		if (valid_perfect_hash(&cp)) {
			cp.perfect = kcalloc(cp.hash, sizeof(*r), GFP_KERNEL);
			if (!cp.perfect)
				goto errout;
			balloc = 1;
		} else {
			cp.h = kcalloc(cp.hash, sizeof(f), GFP_KERNEL);
			if (!cp.h)
				goto errout;
			balloc = 2;
		}
	}

	if (cp.perfect)
		r = cp.perfect + handle;
	else
		r = tcindex_lookup(&cp, handle) ? : &new_filter_result;

	if (r == &new_filter_result) {
		f = kzalloc(sizeof(*f), GFP_KERNEL);
		if (!f)
			goto errout_alloc;
	}

	if (tb[TCA_TCINDEX_CLASSID]) {
		cr.res.classid = nla_get_u32(tb[TCA_TCINDEX_CLASSID]);
		tcf_bind_filter(tp, &cr.res, base);
	}

	tcf_exts_change(tp, &cr.exts, &e);

	tcf_tree_lock(tp);
	if (old_r && old_r != r)
		memset(old_r, 0, sizeof(*old_r));

	memcpy(p, &cp, sizeof(cp));
	memcpy(r, &cr, sizeof(cr));

	if (r == &new_filter_result) {
		struct tcindex_filter **fp;

		f->key = handle;
		f->result = new_filter_result;
		f->next = NULL;
		for (fp = p->h+(handle % p->hash); *fp; fp = &(*fp)->next)
			/* nothing */;
		*fp = f;
	}
	tcf_tree_unlock(tp);

	return 0;

errout_alloc:
	if (balloc == 1)
		kfree(cp.perfect);
	else if (balloc == 2)
		kfree(cp.h);
errout:
	tcf_exts_destroy(tp, &e);
	return err;
}

static int
tcindex_change(struct tcf_proto *tp, unsigned long base, u32 handle,
	       struct nlattr **tca, unsigned long *arg)
{
	struct nlattr *opt = tca[TCA_OPTIONS];
	struct nlattr *tb[TCA_TCINDEX_MAX + 1];
	struct tcindex_data *p = PRIV(tp);
	struct tcindex_filter_result *r = (struct tcindex_filter_result *) *arg;
	int err;

	pr_debug("tcindex_change(tp %p,handle 0x%08x,tca %p,arg %p),opt %p,"
	    "p %p,r %p,*arg 0x%lx\n",
	    tp, handle, tca, arg, opt, p, r, arg ? *arg : 0L);

	if (!opt)
		return 0;

	err = nla_parse_nested(tb, TCA_TCINDEX_MAX, opt, tcindex_policy);
	if (err < 0)
		return err;

	return tcindex_set_parms(tp, base, handle, p, r, tb, tca[TCA_RATE]);
}


static void tcindex_walk(struct tcf_proto *tp, struct tcf_walker *walker)
{
	struct tcindex_data *p = PRIV(tp);
	struct tcindex_filter *f, *next;
	int i;

	pr_debug("tcindex_walk(tp %p,walker %p),p %p\n", tp, walker, p);
	if (p->perfect) {
		for (i = 0; i < p->hash; i++) {
			if (!p->perfect[i].res.class)
				continue;
			if (walker->count >= walker->skip) {
				if (walker->fn(tp,
				    (unsigned long) (p->perfect+i), walker)
				     < 0) {
					walker->stop = 1;
					return;
				}
			}
			walker->count++;
		}
	}
	if (!p->h)
		return;
	for (i = 0; i < p->hash; i++) {
		for (f = p->h[i]; f; f = next) {
			next = f->next;
			if (walker->count >= walker->skip) {
				if (walker->fn(tp, (unsigned long) &f->result,
				    walker) < 0) {
					walker->stop = 1;
					return;
				}
			}
			walker->count++;
		}
	}
}


static int tcindex_destroy_element(struct tcf_proto *tp,
    unsigned long arg, struct tcf_walker *walker)
{
	return __tcindex_delete(tp, arg, 0);
}


static void tcindex_destroy(struct tcf_proto *tp)
{
	struct tcindex_data *p = PRIV(tp);
	struct tcf_walker walker;

	pr_debug("tcindex_destroy(tp %p),p %p\n", tp, p);
	walker.count = 0;
	walker.skip = 0;
	walker.fn = &tcindex_destroy_element;
	tcindex_walk(tp, &walker);
	kfree(p->perfect);
	kfree(p->h);
	kfree(p);
	tp->root = NULL;
}


static int tcindex_dump(struct tcf_proto *tp, unsigned long fh,
    struct sk_buff *skb, struct tcmsg *t)
{
	struct tcindex_data *p = PRIV(tp);
	struct tcindex_filter_result *r = (struct tcindex_filter_result *) fh;
	unsigned char *b = skb_tail_pointer(skb);
	struct nlattr *nest;

	pr_debug("tcindex_dump(tp %p,fh 0x%lx,skb %p,t %p),p %p,r %p,b %p\n",
		 tp, fh, skb, t, p, r, b);
	pr_debug("p->perfect %p p->h %p\n", p->perfect, p->h);

	nest = nla_nest_start(skb, TCA_OPTIONS);
	if (nest == NULL)
		goto nla_put_failure;

	if (!fh) {
		t->tcm_handle = ~0; /* whatever ... */
		NLA_PUT_U32(skb, TCA_TCINDEX_HASH, p->hash);
		NLA_PUT_U16(skb, TCA_TCINDEX_MASK, p->mask);
		NLA_PUT_U32(skb, TCA_TCINDEX_SHIFT, p->shift);
		NLA_PUT_U32(skb, TCA_TCINDEX_FALL_THROUGH, p->fall_through);
		nla_nest_end(skb, nest);
	} else {
		if (p->perfect) {
			t->tcm_handle = r-p->perfect;
		} else {
			struct tcindex_filter *f;
			int i;

			t->tcm_handle = 0;
			for (i = 0; !t->tcm_handle && i < p->hash; i++) {
				for (f = p->h[i]; !t->tcm_handle && f;
				     f = f->next) {
					if (&f->result == r)
						t->tcm_handle = f->key;
				}
			}
		}
		pr_debug("handle = %d\n", t->tcm_handle);
		if (r->res.class)
			NLA_PUT_U32(skb, TCA_TCINDEX_CLASSID, r->res.classid);

		if (tcf_exts_dump(skb, &r->exts, &tcindex_ext_map) < 0)
			goto nla_put_failure;
		nla_nest_end(skb, nest);

		if (tcf_exts_dump_stats(skb, &r->exts, &tcindex_ext_map) < 0)
			goto nla_put_failure;
	}

	return skb->len;

nla_put_failure:
	nlmsg_trim(skb, b);
	return -1;
}

static struct tcf_proto_ops cls_tcindex_ops __read_mostly = {
	.kind		=	"tcindex",
	.classify	=	tcindex_classify,
	.init		=	tcindex_init,
	.destroy	=	tcindex_destroy,
	.get		=	tcindex_get,
	.put		=	tcindex_put,
	.change		=	tcindex_change,
	.delete		=	tcindex_delete,
	.walk		=	tcindex_walk,
	.dump		=	tcindex_dump,
	.owner		=	THIS_MODULE,
};

static int __init init_tcindex(void)
{
	return register_tcf_proto_ops(&cls_tcindex_ops);
}

static void __exit exit_tcindex(void)
{
	unregister_tcf_proto_ops(&cls_tcindex_ops);
}

module_init(init_tcindex)
module_exit(exit_tcindex)
MODULE_LICENSE("GPL");