wme.c revision f9d540ee5f7e480339911df8d7389ef4c435ab54 
1/*
2 * Copyright 2004, Instant802 Networks, Inc.
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 */
8
9#include <linux/netdevice.h>
10#include <linux/skbuff.h>
11#include <linux/module.h>
12#include <linux/if_arp.h>
13#include <linux/types.h>
14#include <net/ip.h>
15#include <net/pkt_sched.h>
16
17#include <net/mac80211.h>
18#include "ieee80211_i.h"
19#include "wme.h"
20
21/* maximum number of hardware queues we support. */
22#define TC_80211_MAX_QUEUES 8
23
24struct ieee80211_sched_data
25{
26	struct tcf_proto *filter_list;
27	struct Qdisc *queues[TC_80211_MAX_QUEUES];
28	struct sk_buff_head requeued[TC_80211_MAX_QUEUES];
29};
30
31
32/* given a data frame determine the 802.1p/1d tag to use */
33static inline unsigned classify_1d(struct sk_buff *skb, struct Qdisc *qd)
34{
35	struct iphdr *ip;
36	int dscp;
37	int offset;
38
39	struct ieee80211_sched_data *q = qdisc_priv(qd);
40	struct tcf_result res = { -1, 0 };
41
42	/* if there is a user set filter list, call out to that */
43	if (q->filter_list) {
44		tc_classify(skb, q->filter_list, &res);
45		if (res.class != -1)
46			return res.class;
47	}
48
49	/* skb->priority values from 256->263 are magic values to
50	 * directly indicate a specific 802.1d priority.
51	 * This is used to allow 802.1d priority to be passed directly in
52	 * from VLAN tags, etc. */
53	if (skb->priority >= 256 && skb->priority <= 263)
54		return skb->priority - 256;
55
56	/* check there is a valid IP header present */
57	offset = ieee80211_get_hdrlen_from_skb(skb) + 8 /* LLC + proto */;
58	if (skb->protocol != __constant_htons(ETH_P_IP) ||
59	    skb->len < offset + sizeof(*ip))
60		return 0;
61
62	ip = (struct iphdr *) (skb->data + offset);
63
64	dscp = ip->tos & 0xfc;
65	if (dscp & 0x1c)
66		return 0;
67	return dscp >> 5;
68}
69
70
71static inline int wme_downgrade_ac(struct sk_buff *skb)
72{
73	switch (skb->priority) {
74	case 6:
75	case 7:
76		skb->priority = 5; /* VO -> VI */
77		return 0;
78	case 4:
79	case 5:
80		skb->priority = 3; /* VI -> BE */
81		return 0;
82	case 0:
83	case 3:
84		skb->priority = 2; /* BE -> BK */
85		return 0;
86	default:
87		return -1;
88	}
89}
90
91
92/* positive return value indicates which queue to use
93 * negative return value indicates to drop the frame */
94static inline int classify80211(struct sk_buff *skb, struct Qdisc *qd)
95{
96	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
97	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
98	unsigned short fc = le16_to_cpu(hdr->frame_control);
99	int qos;
100	const int ieee802_1d_to_ac[8] = { 2, 3, 3, 2, 1, 1, 0, 0 };
101
102	/* see if frame is data or non data frame */
103	if (unlikely((fc & IEEE80211_FCTL_FTYPE) != IEEE80211_FTYPE_DATA)) {
104		/* management frames go on AC_VO queue, but are sent
105		* without QoS control fields */
106		return IEEE80211_TX_QUEUE_DATA0;
107	}
108
109	if (0 /* injected */) {
110		/* use AC from radiotap */
111	}
112
113	/* is this a QoS frame? */
114	qos = fc & IEEE80211_STYPE_QOS_DATA;
115
116	if (!qos) {
117		skb->priority = 0; /* required for correct WPA/11i MIC */
118		return ieee802_1d_to_ac[skb->priority];
119	}
120
121	/* use the data classifier to determine what 802.1d tag the
122	 * data frame has */
123	skb->priority = classify_1d(skb, qd);
124
125	/* in case we are a client verify acm is not set for this ac */
126	while (unlikely(local->wmm_acm & BIT(skb->priority))) {
127		if (wme_downgrade_ac(skb)) {
128			/* No AC with lower priority has acm=0, drop packet. */
129			return -1;
130		}
131	}
132
133	/* look up which queue to use for frames with this 1d tag */
134	return ieee802_1d_to_ac[skb->priority];
135}
136
137
138static int wme_qdiscop_enqueue(struct sk_buff *skb, struct Qdisc* qd)
139{
140	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
141	struct ieee80211_sched_data *q = qdisc_priv(qd);
142	struct ieee80211_tx_packet_data *pkt_data =
143		(struct ieee80211_tx_packet_data *) skb->cb;
144	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
145	unsigned short fc = le16_to_cpu(hdr->frame_control);
146	struct Qdisc *qdisc;
147	int err, queue;
148
149	if (pkt_data->flags & IEEE80211_TXPD_REQUEUE) {
150		skb_queue_tail(&q->requeued[pkt_data->queue], skb);
151		qd->q.qlen++;
152		return 0;
153	}
154
155	queue = classify80211(skb, qd);
156
157	/* now we know the 1d priority, fill in the QoS header if there is one
158	 */
159	if (WLAN_FC_IS_QOS_DATA(fc)) {
160		u8 *p = skb->data + ieee80211_get_hdrlen(fc) - 2;
161		u8 qos_hdr = skb->priority & QOS_CONTROL_TAG1D_MASK;
162		if (local->wifi_wme_noack_test)
163			qos_hdr |= QOS_CONTROL_ACK_POLICY_NOACK <<
164					QOS_CONTROL_ACK_POLICY_SHIFT;
165		/* qos header is 2 bytes, second reserved */
166		*p = qos_hdr;
167		p++;
168		*p = 0;
169	}
170
171	if (unlikely(queue >= local->hw.queues)) {
172#if 0
173		if (net_ratelimit()) {
174			printk(KERN_DEBUG "%s - queue=%d (hw does not "
175			       "support) -> %d\n",
176			       __func__, queue, local->hw.queues - 1);
177		}
178#endif
179		queue = local->hw.queues - 1;
180	}
181
182	if (unlikely(queue < 0)) {
183			kfree_skb(skb);
184			err = NET_XMIT_DROP;
185	} else {
186		pkt_data->queue = (unsigned int) queue;
187		qdisc = q->queues[queue];
188		err = qdisc->enqueue(skb, qdisc);
189		if (err == NET_XMIT_SUCCESS) {
190			qd->q.qlen++;
191			qd->bstats.bytes += skb->len;
192			qd->bstats.packets++;
193			return NET_XMIT_SUCCESS;
194		}
195	}
196	qd->qstats.drops++;
197	return err;
198}
199
200
201/* TODO: clean up the cases where master_hard_start_xmit
202 * returns non 0 - it shouldn't ever do that. Once done we
203 * can remove this function */
204static int wme_qdiscop_requeue(struct sk_buff *skb, struct Qdisc* qd)
205{
206	struct ieee80211_sched_data *q = qdisc_priv(qd);
207	struct ieee80211_tx_packet_data *pkt_data =
208		(struct ieee80211_tx_packet_data *) skb->cb;
209	struct Qdisc *qdisc;
210	int err;
211
212	/* we recorded which queue to use earlier! */
213	qdisc = q->queues[pkt_data->queue];
214
215	if ((err = qdisc->ops->requeue(skb, qdisc)) == 0) {
216		qd->q.qlen++;
217		return 0;
218	}
219	qd->qstats.drops++;
220	return err;
221}
222
223
224static struct sk_buff *wme_qdiscop_dequeue(struct Qdisc* qd)
225{
226	struct ieee80211_sched_data *q = qdisc_priv(qd);
227	struct net_device *dev = qd->dev;
228	struct ieee80211_local *local = wdev_priv(dev->ieee80211_ptr);
229	struct ieee80211_hw *hw = &local->hw;
230	struct sk_buff *skb;
231	struct Qdisc *qdisc;
232	int queue;
233
234	/* check all the h/w queues in numeric/priority order */
235	for (queue = 0; queue < hw->queues; queue++) {
236		/* see if there is room in this hardware queue */
237		if (test_bit(IEEE80211_LINK_STATE_XOFF,
238			     &local->state[queue]) ||
239		    test_bit(IEEE80211_LINK_STATE_PENDING,
240			     &local->state[queue]))
241			continue;
242
243		/* there is space - try and get a frame */
244		skb = skb_dequeue(&q->requeued[queue]);
245		if (skb) {
246			qd->q.qlen--;
247			return skb;
248		}
249
250		qdisc = q->queues[queue];
251		skb = qdisc->dequeue(qdisc);
252		if (skb) {
253			qd->q.qlen--;
254			return skb;
255		}
256	}
257	/* returning a NULL here when all the h/w queues are full means we
258	 * never need to call netif_stop_queue in the driver */
259	return NULL;
260}
261
262
263static void wme_qdiscop_reset(struct Qdisc* qd)
264{
265	struct ieee80211_sched_data *q = qdisc_priv(qd);
266	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
267	struct ieee80211_hw *hw = &local->hw;
268	int queue;
269
270	/* QUESTION: should we have some hardware flush functionality here? */
271
272	for (queue = 0; queue < hw->queues; queue++) {
273		skb_queue_purge(&q->requeued[queue]);
274		qdisc_reset(q->queues[queue]);
275	}
276	qd->q.qlen = 0;
277}
278
279
280static void wme_qdiscop_destroy(struct Qdisc* qd)
281{
282	struct ieee80211_sched_data *q = qdisc_priv(qd);
283	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
284	struct ieee80211_hw *hw = &local->hw;
285	int queue;
286
287	tcf_destroy_chain(q->filter_list);
288	q->filter_list = NULL;
289
290	for (queue=0; queue < hw->queues; queue++) {
291		skb_queue_purge(&q->requeued[queue]);
292		qdisc_destroy(q->queues[queue]);
293		q->queues[queue] = &noop_qdisc;
294	}
295}
296
297
298/* called whenever parameters are updated on existing qdisc */
299static int wme_qdiscop_tune(struct Qdisc *qd, struct rtattr *opt)
300{
301/*	struct ieee80211_sched_data *q = qdisc_priv(qd);
302*/
303	/* check our options block is the right size */
304	/* copy any options to our local structure */
305/*	Ignore options block for now - always use static mapping
306	struct tc_ieee80211_qopt *qopt = RTA_DATA(opt);
307
308	if (opt->rta_len < RTA_LENGTH(sizeof(*qopt)))
309		return -EINVAL;
310	memcpy(q->tag2queue, qopt->tag2queue, sizeof(qopt->tag2queue));
311*/
312	return 0;
313}
314
315
316/* called during initial creation of qdisc on device */
317static int wme_qdiscop_init(struct Qdisc *qd, struct rtattr *opt)
318{
319	struct ieee80211_sched_data *q = qdisc_priv(qd);
320	struct net_device *dev = qd->dev;
321	struct ieee80211_local *local;
322	int queues;
323	int err = 0, i;
324
325	/* check that device is a mac80211 device */
326	if (!dev->ieee80211_ptr ||
327	    dev->ieee80211_ptr->wiphy->privid != mac80211_wiphy_privid)
328		return -EINVAL;
329
330	/* check this device is an ieee80211 master type device */
331	if (dev->type != ARPHRD_IEEE80211)
332		return -EINVAL;
333
334	/* check that there is no qdisc currently attached to device
335	 * this ensures that we will be the root qdisc. (I can't find a better
336	 * way to test this explicitly) */
337	if (dev->qdisc_sleeping != &noop_qdisc)
338		return -EINVAL;
339
340	if (qd->flags & TCQ_F_INGRESS)
341		return -EINVAL;
342
343	local = wdev_priv(dev->ieee80211_ptr);
344	queues = local->hw.queues;
345
346	/* if options were passed in, set them */
347	if (opt) {
348		err = wme_qdiscop_tune(qd, opt);
349	}
350
351	/* create child queues */
352	for (i = 0; i < queues; i++) {
353		skb_queue_head_init(&q->requeued[i]);
354		q->queues[i] = qdisc_create_dflt(qd->dev, &pfifo_qdisc_ops,
355						 qd->handle);
356		if (!q->queues[i]) {
357			q->queues[i] = &noop_qdisc;
358			printk(KERN_ERR "%s child qdisc %i creation failed", dev->name, i);
359		}
360	}
361
362	return err;
363}
364
365static int wme_qdiscop_dump(struct Qdisc *qd, struct sk_buff *skb)
366{
367/*	struct ieee80211_sched_data *q = qdisc_priv(qd);
368	unsigned char *p = skb->tail;
369	struct tc_ieee80211_qopt opt;
370
371	memcpy(&opt.tag2queue, q->tag2queue, TC_80211_MAX_TAG + 1);
372	RTA_PUT(skb, TCA_OPTIONS, sizeof(opt), &opt);
373*/	return skb->len;
374/*
375rtattr_failure:
376	skb_trim(skb, p - skb->data);*/
377	return -1;
378}
379
380
381static int wme_classop_graft(struct Qdisc *qd, unsigned long arg,
382			     struct Qdisc *new, struct Qdisc **old)
383{
384	struct ieee80211_sched_data *q = qdisc_priv(qd);
385	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
386	struct ieee80211_hw *hw = &local->hw;
387	unsigned long queue = arg - 1;
388
389	if (queue >= hw->queues)
390		return -EINVAL;
391
392	if (!new)
393		new = &noop_qdisc;
394
395	sch_tree_lock(qd);
396	*old = q->queues[queue];
397	q->queues[queue] = new;
398	qdisc_reset(*old);
399	sch_tree_unlock(qd);
400
401	return 0;
402}
403
404
405static struct Qdisc *
406wme_classop_leaf(struct Qdisc *qd, unsigned long arg)
407{
408	struct ieee80211_sched_data *q = qdisc_priv(qd);
409	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
410	struct ieee80211_hw *hw = &local->hw;
411	unsigned long queue = arg - 1;
412
413	if (queue >= hw->queues)
414		return NULL;
415
416	return q->queues[queue];
417}
418
419
420static unsigned long wme_classop_get(struct Qdisc *qd, u32 classid)
421{
422	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
423	struct ieee80211_hw *hw = &local->hw;
424	unsigned long queue = TC_H_MIN(classid);
425
426	if (queue - 1 >= hw->queues)
427		return 0;
428
429	return queue;
430}
431
432
433static unsigned long wme_classop_bind(struct Qdisc *qd, unsigned long parent,
434				      u32 classid)
435{
436	return wme_classop_get(qd, classid);
437}
438
439
440static void wme_classop_put(struct Qdisc *q, unsigned long cl)
441{
442}
443
444
445static int wme_classop_change(struct Qdisc *qd, u32 handle, u32 parent,
446			      struct rtattr **tca, unsigned long *arg)
447{
448	unsigned long cl = *arg;
449	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
450	struct ieee80211_hw *hw = &local->hw;
451
452	if (cl - 1 > hw->queues)
453		return -ENOENT;
454
455	/* TODO: put code to program hardware queue parameters here,
456	 * to allow programming from tc command line */
457
458	return 0;
459}
460
461
462/* we don't support deleting hardware queues
463 * when we add WMM-SA support - TSPECs may be deleted here */
464static int wme_classop_delete(struct Qdisc *qd, unsigned long cl)
465{
466	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
467	struct ieee80211_hw *hw = &local->hw;
468
469	if (cl - 1 > hw->queues)
470		return -ENOENT;
471	return 0;
472}
473
474
475static int wme_classop_dump_class(struct Qdisc *qd, unsigned long cl,
476				  struct sk_buff *skb, struct tcmsg *tcm)
477{
478	struct ieee80211_sched_data *q = qdisc_priv(qd);
479	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
480	struct ieee80211_hw *hw = &local->hw;
481
482	if (cl - 1 > hw->queues)
483		return -ENOENT;
484	tcm->tcm_handle = TC_H_MIN(cl);
485	tcm->tcm_parent = qd->handle;
486	tcm->tcm_info = q->queues[cl-1]->handle; /* do we need this? */
487	return 0;
488}
489
490
491static void wme_classop_walk(struct Qdisc *qd, struct qdisc_walker *arg)
492{
493	struct ieee80211_local *local = wdev_priv(qd->dev->ieee80211_ptr);
494	struct ieee80211_hw *hw = &local->hw;
495	int queue;
496
497	if (arg->stop)
498		return;
499
500	for (queue = 0; queue < hw->queues; queue++) {
501		if (arg->count < arg->skip) {
502			arg->count++;
503			continue;
504		}
505		/* we should return classids for our internal queues here
506		 * as well as the external ones */
507		if (arg->fn(qd, queue+1, arg) < 0) {
508			arg->stop = 1;
509			break;
510		}
511		arg->count++;
512	}
513}
514
515
516static struct tcf_proto ** wme_classop_find_tcf(struct Qdisc *qd,
517						unsigned long cl)
518{
519	struct ieee80211_sched_data *q = qdisc_priv(qd);
520
521	if (cl)
522		return NULL;
523
524	return &q->filter_list;
525}
526
527
528/* this qdisc is classful (i.e. has classes, some of which may have leaf qdiscs attached)
529 * - these are the operations on the classes */
530static struct Qdisc_class_ops class_ops =
531{
532	.graft = wme_classop_graft,
533	.leaf = wme_classop_leaf,
534
535	.get = wme_classop_get,
536	.put = wme_classop_put,
537	.change = wme_classop_change,
538	.delete = wme_classop_delete,
539	.walk = wme_classop_walk,
540
541	.tcf_chain = wme_classop_find_tcf,
542	.bind_tcf = wme_classop_bind,
543	.unbind_tcf = wme_classop_put,
544
545	.dump = wme_classop_dump_class,
546};
547
548
549/* queueing discipline operations */
550static struct Qdisc_ops wme_qdisc_ops =
551{
552	.next = NULL,
553	.cl_ops = &class_ops,
554	.id = "ieee80211",
555	.priv_size = sizeof(struct ieee80211_sched_data),
556
557	.enqueue = wme_qdiscop_enqueue,
558	.dequeue = wme_qdiscop_dequeue,
559	.requeue = wme_qdiscop_requeue,
560	.drop = NULL, /* drop not needed since we are always the root qdisc */
561
562	.init = wme_qdiscop_init,
563	.reset = wme_qdiscop_reset,
564	.destroy = wme_qdiscop_destroy,
565	.change = wme_qdiscop_tune,
566
567	.dump = wme_qdiscop_dump,
568};
569
570
571void ieee80211_install_qdisc(struct net_device *dev)
572{
573	struct Qdisc *qdisc;
574
575	qdisc = qdisc_create_dflt(dev, &wme_qdisc_ops, TC_H_ROOT);
576	if (!qdisc) {
577		printk(KERN_ERR "%s: qdisc installation failed\n", dev->name);
578		return;
579	}
580
581	/* same handle as would be allocated by qdisc_alloc_handle() */
582	qdisc->handle = 0x80010000;
583
584	qdisc_lock_tree(dev);
585	list_add_tail(&qdisc->list, &dev->qdisc_list);
586	dev->qdisc_sleeping = qdisc;
587	qdisc_unlock_tree(dev);
588}
589
590
591int ieee80211_qdisc_installed(struct net_device *dev)
592{
593	return dev->qdisc_sleeping->ops == &wme_qdisc_ops;
594}
595
596
597int ieee80211_wme_register(void)
598{
599	return register_qdisc(&wme_qdisc_ops);
600}
601
602
603void ieee80211_wme_unregister(void)
604{
605	unregister_qdisc(&wme_qdisc_ops);
606}
607