sch_atm.c 18.9 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681
/* net/sched/sch_atm.c - ATM VC selection "queueing discipline" */

/* Written 1998-2000 by Werner Almesberger, EPFL ICA */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/atmdev.h>
#include <linux/atmclip.h>
#include <linux/rtnetlink.h>
#include <linux/file.h>		/* for fput */
#include <net/netlink.h>
#include <net/pkt_sched.h>

/*
 * The ATM queuing discipline provides a framework for invoking classifiers
 * (aka "filters"), which in turn select classes of this queuing discipline.
 * Each class maps the flow(s) it is handling to a given VC. Multiple classes
 * may share the same VC.
 *
 * When creating a class, VCs are specified by passing the number of the open
 * socket descriptor by which the calling process references the VC. The kernel
 * keeps the VC open at least until all classes using it are removed.
 *
 * In this file, most functions are named atm_tc_* to avoid confusion with all
 * the atm_* in net/atm. This naming convention differs from what's used in the
 * rest of net/sched.
 *
 * Known bugs:
 *  - sometimes messes up the IP stack
 *  - any manipulations besides the few operations described in the README, are
 *    untested and likely to crash the system
 *  - should lock the flow while there is data in the queue (?)
 */

#define VCC2FLOW(vcc) ((struct atm_flow_data *) ((vcc)->user_back))

struct atm_flow_data {
	struct Qdisc		*q;	/* FIFO, TBF, etc. */
	struct tcf_proto __rcu	*filter_list;
	struct atm_vcc		*vcc;	/* VCC; NULL if VCC is closed */
	void			(*old_pop)(struct atm_vcc *vcc,
					   struct sk_buff *skb); /* chaining */
	struct atm_qdisc_data	*parent;	/* parent qdisc */
	struct socket		*sock;		/* for closing */
	u32			classid;	/* x:y type ID */
	int			ref;		/* reference count */
	struct gnet_stats_basic_packed	bstats;
	struct gnet_stats_queue	qstats;
	struct list_head	list;
	struct atm_flow_data	*excess;	/* flow for excess traffic;
						   NULL to set CLP instead */
	int			hdr_len;
	unsigned char		hdr[0];		/* header data; MUST BE LAST */
};

struct atm_qdisc_data {
	struct atm_flow_data	link;		/* unclassified skbs go here */
	struct list_head	flows;		/* NB: "link" is also on this
						   list */
	struct tasklet_struct	task;		/* dequeue tasklet */
};

/* ------------------------- Class/flow operations ------------------------- */

static inline struct atm_flow_data *lookup_flow(struct Qdisc *sch, u32 classid)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);
	struct atm_flow_data *flow;

	list_for_each_entry(flow, &p->flows, list) {
		if (flow->classid == classid)
			return flow;
	}
	return NULL;
}

static int atm_tc_graft(struct Qdisc *sch, unsigned long arg,
			struct Qdisc *new, struct Qdisc **old)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);
	struct atm_flow_data *flow = (struct atm_flow_data *)arg;

	pr_debug("atm_tc_graft(sch %p,[qdisc %p],flow %p,new %p,old %p)\n",
		sch, p, flow, new, old);
	if (list_empty(&flow->list))
		return -EINVAL;
	if (!new)
		new = &noop_qdisc;
	*old = flow->q;
	flow->q = new;
	if (*old)
		qdisc_reset(*old);
	return 0;
}

static struct Qdisc *atm_tc_leaf(struct Qdisc *sch, unsigned long cl)
{
	struct atm_flow_data *flow = (struct atm_flow_data *)cl;

	pr_debug("atm_tc_leaf(sch %p,flow %p)\n", sch, flow);
	return flow ? flow->q : NULL;
}

static unsigned long atm_tc_get(struct Qdisc *sch, u32 classid)
{
	struct atm_qdisc_data *p __maybe_unused = qdisc_priv(sch);
	struct atm_flow_data *flow;

	pr_debug("atm_tc_get(sch %p,[qdisc %p],classid %x)\n", sch, p, classid);
	flow = lookup_flow(sch, classid);
	if (flow)
		flow->ref++;
	pr_debug("atm_tc_get: flow %p\n", flow);
	return (unsigned long)flow;
}

static unsigned long atm_tc_bind_filter(struct Qdisc *sch,
					unsigned long parent, u32 classid)
{
	return atm_tc_get(sch, classid);
}

/*
 * atm_tc_put handles all destructions, including the ones that are explicitly
 * requested (atm_tc_destroy, etc.). The assumption here is that we never drop
 * anything that still seems to be in use.
 */
static void atm_tc_put(struct Qdisc *sch, unsigned long cl)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);
	struct atm_flow_data *flow = (struct atm_flow_data *)cl;

	pr_debug("atm_tc_put(sch %p,[qdisc %p],flow %p)\n", sch, p, flow);
	if (--flow->ref)
		return;
	pr_debug("atm_tc_put: destroying\n");
	list_del_init(&flow->list);
	pr_debug("atm_tc_put: qdisc %p\n", flow->q);
	qdisc_destroy(flow->q);
	tcf_destroy_chain(&flow->filter_list);
	if (flow->sock) {
		pr_debug("atm_tc_put: f_count %ld\n",
			file_count(flow->sock->file));
		flow->vcc->pop = flow->old_pop;
		sockfd_put(flow->sock);
	}
	if (flow->excess)
		atm_tc_put(sch, (unsigned long)flow->excess);
	if (flow != &p->link)
		kfree(flow);
	/*
	 * If flow == &p->link, the qdisc no longer works at this point and
	 * needs to be removed. (By the caller of atm_tc_put.)
	 */
}

static void sch_atm_pop(struct atm_vcc *vcc, struct sk_buff *skb)
{
	struct atm_qdisc_data *p = VCC2FLOW(vcc)->parent;

	pr_debug("sch_atm_pop(vcc %p,skb %p,[qdisc %p])\n", vcc, skb, p);
	VCC2FLOW(vcc)->old_pop(vcc, skb);
	tasklet_schedule(&p->task);
}

static const u8 llc_oui_ip[] = {
	0xaa,			/* DSAP: non-ISO */
	0xaa,			/* SSAP: non-ISO */
	0x03,			/* Ctrl: Unnumbered Information Command PDU */
	0x00,			/* OUI: EtherType */
	0x00, 0x00,
	0x08, 0x00
};				/* Ethertype IP (0800) */

static const struct nla_policy atm_policy[TCA_ATM_MAX + 1] = {
	[TCA_ATM_FD]		= { .type = NLA_U32 },
	[TCA_ATM_EXCESS]	= { .type = NLA_U32 },
};

static int atm_tc_change(struct Qdisc *sch, u32 classid, u32 parent,
			 struct nlattr **tca, unsigned long *arg)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);
	struct atm_flow_data *flow = (struct atm_flow_data *)*arg;
	struct atm_flow_data *excess = NULL;
	struct nlattr *opt = tca[TCA_OPTIONS];
	struct nlattr *tb[TCA_ATM_MAX + 1];
	struct socket *sock;
	int fd, error, hdr_len;
	void *hdr;

	pr_debug("atm_tc_change(sch %p,[qdisc %p],classid %x,parent %x,"
		"flow %p,opt %p)\n", sch, p, classid, parent, flow, opt);
	/*
	 * The concept of parents doesn't apply for this qdisc.
	 */
	if (parent && parent != TC_H_ROOT && parent != sch->handle)
		return -EINVAL;
	/*
	 * ATM classes cannot be changed. In order to change properties of the
	 * ATM connection, that socket needs to be modified directly (via the
	 * native ATM API. In order to send a flow to a different VC, the old
	 * class needs to be removed and a new one added. (This may be changed
	 * later.)
	 */
	if (flow)
		return -EBUSY;
	if (opt == NULL)
		return -EINVAL;

	error = nla_parse_nested(tb, TCA_ATM_MAX, opt, atm_policy);
	if (error < 0)
		return error;

	if (!tb[TCA_ATM_FD])
		return -EINVAL;
	fd = nla_get_u32(tb[TCA_ATM_FD]);
	pr_debug("atm_tc_change: fd %d\n", fd);
	if (tb[TCA_ATM_HDR]) {
		hdr_len = nla_len(tb[TCA_ATM_HDR]);
		hdr = nla_data(tb[TCA_ATM_HDR]);
	} else {
		hdr_len = RFC1483LLC_LEN;
		hdr = NULL;	/* default LLC/SNAP for IP */
	}
	if (!tb[TCA_ATM_EXCESS])
		excess = NULL;
	else {
		excess = (struct atm_flow_data *)
			atm_tc_get(sch, nla_get_u32(tb[TCA_ATM_EXCESS]));
		if (!excess)
			return -ENOENT;
	}
	pr_debug("atm_tc_change: type %d, payload %d, hdr_len %d\n",
		 opt->nla_type, nla_len(opt), hdr_len);
	sock = sockfd_lookup(fd, &error);
	if (!sock)
		return error;	/* f_count++ */
	pr_debug("atm_tc_change: f_count %ld\n", file_count(sock->file));
	if (sock->ops->family != PF_ATMSVC && sock->ops->family != PF_ATMPVC) {
		error = -EPROTOTYPE;
		goto err_out;
	}
	/* @@@ should check if the socket is really operational or we'll crash
	   on vcc->send */
	if (classid) {
		if (TC_H_MAJ(classid ^ sch->handle)) {
			pr_debug("atm_tc_change: classid mismatch\n");
			error = -EINVAL;
			goto err_out;
		}
	} else {
		int i;
		unsigned long cl;

		for (i = 1; i < 0x8000; i++) {
			classid = TC_H_MAKE(sch->handle, 0x8000 | i);
			cl = atm_tc_get(sch, classid);
			if (!cl)
				break;
			atm_tc_put(sch, cl);
		}
	}
	pr_debug("atm_tc_change: new id %x\n", classid);
	flow = kzalloc(sizeof(struct atm_flow_data) + hdr_len, GFP_KERNEL);
	pr_debug("atm_tc_change: flow %p\n", flow);
	if (!flow) {
		error = -ENOBUFS;
		goto err_out;
	}
	RCU_INIT_POINTER(flow->filter_list, NULL);
	flow->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, classid);
	if (!flow->q)
		flow->q = &noop_qdisc;
	pr_debug("atm_tc_change: qdisc %p\n", flow->q);
	flow->sock = sock;
	flow->vcc = ATM_SD(sock);	/* speedup */
	flow->vcc->user_back = flow;
	pr_debug("atm_tc_change: vcc %p\n", flow->vcc);
	flow->old_pop = flow->vcc->pop;
	flow->parent = p;
	flow->vcc->pop = sch_atm_pop;
	flow->classid = classid;
	flow->ref = 1;
	flow->excess = excess;
	list_add(&flow->list, &p->link.list);
	flow->hdr_len = hdr_len;
	if (hdr)
		memcpy(flow->hdr, hdr, hdr_len);
	else
		memcpy(flow->hdr, llc_oui_ip, sizeof(llc_oui_ip));
	*arg = (unsigned long)flow;
	return 0;
err_out:
	if (excess)
		atm_tc_put(sch, (unsigned long)excess);
	sockfd_put(sock);
	return error;
}

static int atm_tc_delete(struct Qdisc *sch, unsigned long arg)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);
	struct atm_flow_data *flow = (struct atm_flow_data *)arg;

	pr_debug("atm_tc_delete(sch %p,[qdisc %p],flow %p)\n", sch, p, flow);
	if (list_empty(&flow->list))
		return -EINVAL;
	if (rcu_access_pointer(flow->filter_list) || flow == &p->link)
		return -EBUSY;
	/*
	 * Reference count must be 2: one for "keepalive" (set at class
	 * creation), and one for the reference held when calling delete.
	 */
	if (flow->ref < 2) {
		pr_err("atm_tc_delete: flow->ref == %d\n", flow->ref);
		return -EINVAL;
	}
	if (flow->ref > 2)
		return -EBUSY;	/* catch references via excess, etc. */
	atm_tc_put(sch, arg);
	return 0;
}

static void atm_tc_walk(struct Qdisc *sch, struct qdisc_walker *walker)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);
	struct atm_flow_data *flow;

	pr_debug("atm_tc_walk(sch %p,[qdisc %p],walker %p)\n", sch, p, walker);
	if (walker->stop)
		return;
	list_for_each_entry(flow, &p->flows, list) {
		if (walker->count >= walker->skip &&
		    walker->fn(sch, (unsigned long)flow, walker) < 0) {
			walker->stop = 1;
			break;
		}
		walker->count++;
	}
}

static struct tcf_proto __rcu **atm_tc_find_tcf(struct Qdisc *sch,
						unsigned long cl)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);
	struct atm_flow_data *flow = (struct atm_flow_data *)cl;

	pr_debug("atm_tc_find_tcf(sch %p,[qdisc %p],flow %p)\n", sch, p, flow);
	return flow ? &flow->filter_list : &p->link.filter_list;
}

/* --------------------------- Qdisc operations ---------------------------- */

static int atm_tc_enqueue(struct sk_buff *skb, struct Qdisc *sch,
			  struct sk_buff **to_free)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);
	struct atm_flow_data *flow;
	struct tcf_result res;
	int result;
	int ret = NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;

	pr_debug("atm_tc_enqueue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);
	result = TC_ACT_OK;	/* be nice to gcc */
	flow = NULL;
	if (TC_H_MAJ(skb->priority) != sch->handle ||
	    !(flow = (struct atm_flow_data *)atm_tc_get(sch, skb->priority))) {
		struct tcf_proto *fl;

		list_for_each_entry(flow, &p->flows, list) {
			fl = rcu_dereference_bh(flow->filter_list);
			if (fl) {
				result = tc_classify(skb, fl, &res, true);
				if (result < 0)
					continue;
				flow = (struct atm_flow_data *)res.class;
				if (!flow)
					flow = lookup_flow(sch, res.classid);
				goto done;
			}
		}
		flow = NULL;
done:
		;
	}
	if (!flow) {
		flow = &p->link;
	} else {
		if (flow->vcc)
			ATM_SKB(skb)->atm_options = flow->vcc->atm_options;
		/*@@@ looks good ... but it's not supposed to work :-) */
#ifdef CONFIG_NET_CLS_ACT
		switch (result) {
		case TC_ACT_QUEUED:
		case TC_ACT_STOLEN:
			__qdisc_drop(skb, to_free);
			return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
		case TC_ACT_SHOT:
			__qdisc_drop(skb, to_free);
			goto drop;
		case TC_ACT_RECLASSIFY:
			if (flow->excess)
				flow = flow->excess;
			else
				ATM_SKB(skb)->atm_options |= ATM_ATMOPT_CLP;
			break;
		}
#endif
	}

	ret = qdisc_enqueue(skb, flow->q, to_free);
	if (ret != NET_XMIT_SUCCESS) {
drop: __maybe_unused
		if (net_xmit_drop_count(ret)) {
			qdisc_qstats_drop(sch);
			if (flow)
				flow->qstats.drops++;
		}
		return ret;
	}
	/*
	 * Okay, this may seem weird. We pretend we've dropped the packet if
	 * it goes via ATM. The reason for this is that the outer qdisc
	 * expects to be able to q->dequeue the packet later on if we return
	 * success at this place. Also, sch->q.qdisc needs to reflect whether
	 * there is a packet egligible for dequeuing or not. Note that the
	 * statistics of the outer qdisc are necessarily wrong because of all
	 * this. There's currently no correct solution for this.
	 */
	if (flow == &p->link) {
		sch->q.qlen++;
		return NET_XMIT_SUCCESS;
	}
	tasklet_schedule(&p->task);
	return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
}

/*
 * Dequeue packets and send them over ATM. Note that we quite deliberately
 * avoid checking net_device's flow control here, simply because sch_atm
 * uses its own channels, which have nothing to do with any CLIP/LANE/or
 * non-ATM interfaces.
 */

static void sch_atm_dequeue(unsigned long data)
{
	struct Qdisc *sch = (struct Qdisc *)data;
	struct atm_qdisc_data *p = qdisc_priv(sch);
	struct atm_flow_data *flow;
	struct sk_buff *skb;

	pr_debug("sch_atm_dequeue(sch %p,[qdisc %p])\n", sch, p);
	list_for_each_entry(flow, &p->flows, list) {
		if (flow == &p->link)
			continue;
		/*
		 * If traffic is properly shaped, this won't generate nasty
		 * little bursts. Otherwise, it may ... (but that's okay)
		 */
		while ((skb = flow->q->ops->peek(flow->q))) {
			if (!atm_may_send(flow->vcc, skb->truesize))
				break;

			skb = qdisc_dequeue_peeked(flow->q);
			if (unlikely(!skb))
				break;

			qdisc_bstats_update(sch, skb);
			bstats_update(&flow->bstats, skb);
			pr_debug("atm_tc_dequeue: sending on class %p\n", flow);
			/* remove any LL header somebody else has attached */
			skb_pull(skb, skb_network_offset(skb));
			if (skb_headroom(skb) < flow->hdr_len) {
				struct sk_buff *new;

				new = skb_realloc_headroom(skb, flow->hdr_len);
				dev_kfree_skb(skb);
				if (!new)
					continue;
				skb = new;
			}
			pr_debug("sch_atm_dequeue: ip %p, data %p\n",
				 skb_network_header(skb), skb->data);
			ATM_SKB(skb)->vcc = flow->vcc;
			memcpy(skb_push(skb, flow->hdr_len), flow->hdr,
			       flow->hdr_len);
			atomic_add(skb->truesize,
				   &sk_atm(flow->vcc)->sk_wmem_alloc);
			/* atm.atm_options are already set by atm_tc_enqueue */
			flow->vcc->send(flow->vcc, skb);
		}
	}
}

static struct sk_buff *atm_tc_dequeue(struct Qdisc *sch)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);
	struct sk_buff *skb;

	pr_debug("atm_tc_dequeue(sch %p,[qdisc %p])\n", sch, p);
	tasklet_schedule(&p->task);
	skb = qdisc_dequeue_peeked(p->link.q);
	if (skb)
		sch->q.qlen--;
	return skb;
}

static struct sk_buff *atm_tc_peek(struct Qdisc *sch)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);

	pr_debug("atm_tc_peek(sch %p,[qdisc %p])\n", sch, p);

	return p->link.q->ops->peek(p->link.q);
}

static int atm_tc_init(struct Qdisc *sch, struct nlattr *opt)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);

	pr_debug("atm_tc_init(sch %p,[qdisc %p],opt %p)\n", sch, p, opt);
	INIT_LIST_HEAD(&p->flows);
	INIT_LIST_HEAD(&p->link.list);
	list_add(&p->link.list, &p->flows);
	p->link.q = qdisc_create_dflt(sch->dev_queue,
				      &pfifo_qdisc_ops, sch->handle);
	if (!p->link.q)
		p->link.q = &noop_qdisc;
	pr_debug("atm_tc_init: link (%p) qdisc %p\n", &p->link, p->link.q);
	RCU_INIT_POINTER(p->link.filter_list, NULL);
	p->link.vcc = NULL;
	p->link.sock = NULL;
	p->link.classid = sch->handle;
	p->link.ref = 1;
	tasklet_init(&p->task, sch_atm_dequeue, (unsigned long)sch);
	return 0;
}

static void atm_tc_reset(struct Qdisc *sch)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);
	struct atm_flow_data *flow;

	pr_debug("atm_tc_reset(sch %p,[qdisc %p])\n", sch, p);
	list_for_each_entry(flow, &p->flows, list)
		qdisc_reset(flow->q);
	sch->q.qlen = 0;
}

static void atm_tc_destroy(struct Qdisc *sch)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);
	struct atm_flow_data *flow, *tmp;

	pr_debug("atm_tc_destroy(sch %p,[qdisc %p])\n", sch, p);
	list_for_each_entry(flow, &p->flows, list)
		tcf_destroy_chain(&flow->filter_list);

	list_for_each_entry_safe(flow, tmp, &p->flows, list) {
		if (flow->ref > 1)
			pr_err("atm_destroy: %p->ref = %d\n", flow, flow->ref);
		atm_tc_put(sch, (unsigned long)flow);
	}
	tasklet_kill(&p->task);
}

static int atm_tc_dump_class(struct Qdisc *sch, unsigned long cl,
			     struct sk_buff *skb, struct tcmsg *tcm)
{
	struct atm_qdisc_data *p = qdisc_priv(sch);
	struct atm_flow_data *flow = (struct atm_flow_data *)cl;
	struct nlattr *nest;

	pr_debug("atm_tc_dump_class(sch %p,[qdisc %p],flow %p,skb %p,tcm %p)\n",
		sch, p, flow, skb, tcm);
	if (list_empty(&flow->list))
		return -EINVAL;
	tcm->tcm_handle = flow->classid;
	tcm->tcm_info = flow->q->handle;

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

	if (nla_put(skb, TCA_ATM_HDR, flow->hdr_len, flow->hdr))
		goto nla_put_failure;
	if (flow->vcc) {
		struct sockaddr_atmpvc pvc;
		int state;

		memset(&pvc, 0, sizeof(pvc));
		pvc.sap_family = AF_ATMPVC;
		pvc.sap_addr.itf = flow->vcc->dev ? flow->vcc->dev->number : -1;
		pvc.sap_addr.vpi = flow->vcc->vpi;
		pvc.sap_addr.vci = flow->vcc->vci;
		if (nla_put(skb, TCA_ATM_ADDR, sizeof(pvc), &pvc))
			goto nla_put_failure;
		state = ATM_VF2VS(flow->vcc->flags);
		if (nla_put_u32(skb, TCA_ATM_STATE, state))
			goto nla_put_failure;
	}
	if (flow->excess) {
		if (nla_put_u32(skb, TCA_ATM_EXCESS, flow->classid))
			goto nla_put_failure;
	} else {
		if (nla_put_u32(skb, TCA_ATM_EXCESS, 0))
			goto nla_put_failure;
	}
	return nla_nest_end(skb, nest);

nla_put_failure:
	nla_nest_cancel(skb, nest);
	return -1;
}
static int
atm_tc_dump_class_stats(struct Qdisc *sch, unsigned long arg,
			struct gnet_dump *d)
{
	struct atm_flow_data *flow = (struct atm_flow_data *)arg;

	if (gnet_stats_copy_basic(qdisc_root_sleeping_running(sch),
				  d, NULL, &flow->bstats) < 0 ||
	    gnet_stats_copy_queue(d, NULL, &flow->qstats, flow->q->q.qlen) < 0)
		return -1;

	return 0;
}

static int atm_tc_dump(struct Qdisc *sch, struct sk_buff *skb)
{
	return 0;
}

static const struct Qdisc_class_ops atm_class_ops = {
	.graft		= atm_tc_graft,
	.leaf		= atm_tc_leaf,
	.get		= atm_tc_get,
	.put		= atm_tc_put,
	.change		= atm_tc_change,
	.delete		= atm_tc_delete,
	.walk		= atm_tc_walk,
	.tcf_chain	= atm_tc_find_tcf,
	.bind_tcf	= atm_tc_bind_filter,
	.unbind_tcf	= atm_tc_put,
	.dump		= atm_tc_dump_class,
	.dump_stats	= atm_tc_dump_class_stats,
};

static struct Qdisc_ops atm_qdisc_ops __read_mostly = {
	.cl_ops		= &atm_class_ops,
	.id		= "atm",
	.priv_size	= sizeof(struct atm_qdisc_data),
	.enqueue	= atm_tc_enqueue,
	.dequeue	= atm_tc_dequeue,
	.peek		= atm_tc_peek,
	.init		= atm_tc_init,
	.reset		= atm_tc_reset,
	.destroy	= atm_tc_destroy,
	.dump		= atm_tc_dump,
	.owner		= THIS_MODULE,
};

static int __init atm_init(void)
{
	return register_qdisc(&atm_qdisc_ops);
}

static void __exit atm_exit(void)
{
	unregister_qdisc(&atm_qdisc_ops);
}

module_init(atm_init)
module_exit(atm_exit)
MODULE_LICENSE("GPL");