1/* net/sched/sch_dsmark.c - Differentiated Services field marker */
2
3/* Written 1998-2000 by Werner Almesberger, EPFL ICA */
4
5
6#include <linux/module.h>
7#include <linux/init.h>
8#include <linux/types.h>
9#include <linux/string.h>
10#include <linux/errno.h>
11#include <linux/skbuff.h>
12#include <linux/netdevice.h> /* for pkt_sched */
13#include <linux/rtnetlink.h>
14#include <net/pkt_sched.h>
15#include <net/dsfield.h>
16#include <net/inet_ecn.h>
17#include <asm/byteorder.h>
18
19
20#define DPRINTK(format,args...)
21
22#define D2PRINTK(format,args...)
23
24
25#define PRIV(sch) ((struct dsmark_qdisc_data *) qdisc_priv(sch))
26
27
28/*
29 * classid	class		marking
30 * -------	-----		-------
31 *   n/a	  0		n/a
32 *   x:0	  1		use entry [0]
33 *   ...	 ...		...
34 *   x:y y>0	 y+1		use entry [y]
35 *   ...	 ...		...
36 * x:indices-1	indices		use entry [indices-1]
37 *   ...	 ...		...
38 *   x:y	 y+1		use entry [y & (indices-1)]
39 *   ...	 ...		...
40 * 0xffff	0x10000		use entry [indices-1]
41 */
42
43
44#define NO_DEFAULT_INDEX	(1 << 16)
45
46struct dsmark_qdisc_data {
47	struct Qdisc		*q;
48	struct tcf_proto	*filter_list;
49	u8			*mask;	/* "owns" the array */
50	u8			*value;
51	u16			indices;
52	u32			default_index;	/* index range is 0...0xffff */
53	int			set_tc_index;
54};
55
56static inline int dsmark_valid_indices(u16 indices)
57{
58	while (indices != 1) {
59		if (indices & 1)
60			return 0;
61		indices >>= 1;
62	}
63
64	return 1;
65}
66
67static inline int dsmark_valid_index(struct dsmark_qdisc_data *p, u16 index)
68{
69	return (index <= p->indices && index > 0);
70}
71
72/* ------------------------- Class/flow operations ------------------------- */
73
74static int dsmark_graft(struct Qdisc *sch, unsigned long arg,
75			struct Qdisc *new, struct Qdisc **old)
76{
77	struct dsmark_qdisc_data *p = PRIV(sch);
78
79	DPRINTK("dsmark_graft(sch %p,[qdisc %p],new %p,old %p)\n",
80		sch, p, new, old);
81
82	if (new == NULL) {
83		new = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops,
84					sch->handle);
85		if (new == NULL)
86			new = &noop_qdisc;
87	}
88
89	sch_tree_lock(sch);
90	*old = xchg(&p->q, new);
91	qdisc_tree_decrease_qlen(*old, (*old)->q.qlen);
92	qdisc_reset(*old);
93	sch_tree_unlock(sch);
94
95	return 0;
96}
97
98static struct Qdisc *dsmark_leaf(struct Qdisc *sch, unsigned long arg)
99{
100	return PRIV(sch)->q;
101}
102
103static unsigned long dsmark_get(struct Qdisc *sch, u32 classid)
104{
105	DPRINTK("dsmark_get(sch %p,[qdisc %p],classid %x)\n",
106		sch, PRIV(sch), classid);
107
108	return TC_H_MIN(classid) + 1;
109}
110
111static unsigned long dsmark_bind_filter(struct Qdisc *sch,
112					unsigned long parent, u32 classid)
113{
114	return dsmark_get(sch, classid);
115}
116
117static void dsmark_put(struct Qdisc *sch, unsigned long cl)
118{
119}
120
121static int dsmark_change(struct Qdisc *sch, u32 classid, u32 parent,
122			 struct rtattr **tca, unsigned long *arg)
123{
124	struct dsmark_qdisc_data *p = PRIV(sch);
125	struct rtattr *opt = tca[TCA_OPTIONS-1];
126	struct rtattr *tb[TCA_DSMARK_MAX];
127	int err = -EINVAL;
128	u8 mask = 0;
129
130	DPRINTK("dsmark_change(sch %p,[qdisc %p],classid %x,parent %x),"
131		"arg 0x%lx\n", sch, p, classid, parent, *arg);
132
133	if (!dsmark_valid_index(p, *arg)) {
134		err = -ENOENT;
135		goto rtattr_failure;
136	}
137
138	if (!opt || rtattr_parse_nested(tb, TCA_DSMARK_MAX, opt))
139		goto rtattr_failure;
140
141	if (tb[TCA_DSMARK_MASK-1])
142		mask = RTA_GET_U8(tb[TCA_DSMARK_MASK-1]);
143
144	if (tb[TCA_DSMARK_VALUE-1])
145		p->value[*arg-1] = RTA_GET_U8(tb[TCA_DSMARK_VALUE-1]);
146
147	if (tb[TCA_DSMARK_MASK-1])
148		p->mask[*arg-1] = mask;
149
150	err = 0;
151
152rtattr_failure:
153	return err;
154}
155
156static int dsmark_delete(struct Qdisc *sch, unsigned long arg)
157{
158	struct dsmark_qdisc_data *p = PRIV(sch);
159
160	if (!dsmark_valid_index(p, arg))
161		return -EINVAL;
162
163	p->mask[arg-1] = 0xff;
164	p->value[arg-1] = 0;
165
166	return 0;
167}
168
169static void dsmark_walk(struct Qdisc *sch,struct qdisc_walker *walker)
170{
171	struct dsmark_qdisc_data *p = PRIV(sch);
172	int i;
173
174	DPRINTK("dsmark_walk(sch %p,[qdisc %p],walker %p)\n", sch, p, walker);
175
176	if (walker->stop)
177		return;
178
179	for (i = 0; i < p->indices; i++) {
180		if (p->mask[i] == 0xff && !p->value[i])
181			goto ignore;
182		if (walker->count >= walker->skip) {
183			if (walker->fn(sch, i+1, walker) < 0) {
184				walker->stop = 1;
185				break;
186			}
187		}
188ignore:
189		walker->count++;
190	}
191}
192
193static struct tcf_proto **dsmark_find_tcf(struct Qdisc *sch,unsigned long cl)
194{
195	return &PRIV(sch)->filter_list;
196}
197
198/* --------------------------- Qdisc operations ---------------------------- */
199
200static int dsmark_enqueue(struct sk_buff *skb,struct Qdisc *sch)
201{
202	struct dsmark_qdisc_data *p = PRIV(sch);
203	int err;
204
205	D2PRINTK("dsmark_enqueue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);
206
207	if (p->set_tc_index) {
208		switch (skb->protocol) {
209			case __constant_htons(ETH_P_IP):
210				skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
211					& ~INET_ECN_MASK;
212				break;
213			case __constant_htons(ETH_P_IPV6):
214				skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
215					& ~INET_ECN_MASK;
216				break;
217			default:
218				skb->tc_index = 0;
219				break;
220		}
221	}
222
223	if (TC_H_MAJ(skb->priority) == sch->handle)
224		skb->tc_index = TC_H_MIN(skb->priority);
225	else {
226		struct tcf_result res;
227		int result = tc_classify(skb, p->filter_list, &res);
228
229		D2PRINTK("result %d class 0x%04x\n", result, res.classid);
230
231		switch (result) {
232#ifdef CONFIG_NET_CLS_POLICE
233			case TC_POLICE_SHOT:
234				kfree_skb(skb);
235				sch->qstats.drops++;
236				return NET_XMIT_POLICED;
237#endif
238			case TC_POLICE_OK:
239				skb->tc_index = TC_H_MIN(res.classid);
240				break;
241			case TC_POLICE_UNSPEC:
242				/* fall through */
243			default:
244				if (p->default_index != NO_DEFAULT_INDEX)
245					skb->tc_index = p->default_index;
246				break;
247		}
248	}
249
250	err = p->q->enqueue(skb,p->q);
251	if (err != NET_XMIT_SUCCESS) {
252		sch->qstats.drops++;
253		return err;
254	}
255
256	sch->bstats.bytes += skb->len;
257	sch->bstats.packets++;
258	sch->q.qlen++;
259
260	return NET_XMIT_SUCCESS;
261}
262
263static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
264{
265	struct dsmark_qdisc_data *p = PRIV(sch);
266	struct sk_buff *skb;
267	u32 index;
268
269	D2PRINTK("dsmark_dequeue(sch %p,[qdisc %p])\n", sch, p);
270
271	skb = p->q->ops->dequeue(p->q);
272	if (skb == NULL)
273		return NULL;
274
275	sch->q.qlen--;
276
277	index = skb->tc_index & (p->indices - 1);
278	D2PRINTK("index %d->%d\n", skb->tc_index, index);
279
280	switch (skb->protocol) {
281		case __constant_htons(ETH_P_IP):
282			ipv4_change_dsfield(ip_hdr(skb), p->mask[index],
283					    p->value[index]);
284			break;
285		case __constant_htons(ETH_P_IPV6):
286			ipv6_change_dsfield(ipv6_hdr(skb), p->mask[index],
287					    p->value[index]);
288			break;
289		default:
290			/*
291			 * Only complain if a change was actually attempted.
292			 * This way, we can send non-IP traffic through dsmark
293			 * and don't need yet another qdisc as a bypass.
294			 */
295			if (p->mask[index] != 0xff || p->value[index])
296				printk(KERN_WARNING "dsmark_dequeue: "
297				       "unsupported protocol %d\n",
298				       ntohs(skb->protocol));
299			break;
300	}
301
302	return skb;
303}
304
305static int dsmark_requeue(struct sk_buff *skb,struct Qdisc *sch)
306{
307	struct dsmark_qdisc_data *p = PRIV(sch);
308	int err;
309
310	D2PRINTK("dsmark_requeue(skb %p,sch %p,[qdisc %p])\n", skb, sch, p);
311
312	err = p->q->ops->requeue(skb, p->q);
313	if (err != NET_XMIT_SUCCESS) {
314		sch->qstats.drops++;
315		return err;
316	}
317
318	sch->q.qlen++;
319	sch->qstats.requeues++;
320
321	return NET_XMIT_SUCCESS;
322}
323
324static unsigned int dsmark_drop(struct Qdisc *sch)
325{
326	struct dsmark_qdisc_data *p = PRIV(sch);
327	unsigned int len;
328
329	DPRINTK("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);
330
331	if (p->q->ops->drop == NULL)
332		return 0;
333
334	len = p->q->ops->drop(p->q);
335	if (len)
336		sch->q.qlen--;
337
338	return len;
339}
340
341static int dsmark_init(struct Qdisc *sch, struct rtattr *opt)
342{
343	struct dsmark_qdisc_data *p = PRIV(sch);
344	struct rtattr *tb[TCA_DSMARK_MAX];
345	int err = -EINVAL;
346	u32 default_index = NO_DEFAULT_INDEX;
347	u16 indices;
348	u8 *mask;
349
350	DPRINTK("dsmark_init(sch %p,[qdisc %p],opt %p)\n", sch, p, opt);
351
352	if (!opt || rtattr_parse_nested(tb, TCA_DSMARK_MAX, opt) < 0)
353		goto errout;
354
355	indices = RTA_GET_U16(tb[TCA_DSMARK_INDICES-1]);
356	if (!indices || !dsmark_valid_indices(indices))
357		goto errout;
358
359	if (tb[TCA_DSMARK_DEFAULT_INDEX-1])
360		default_index = RTA_GET_U16(tb[TCA_DSMARK_DEFAULT_INDEX-1]);
361
362	mask = kmalloc(indices * 2, GFP_KERNEL);
363	if (mask == NULL) {
364		err = -ENOMEM;
365		goto errout;
366	}
367
368	p->mask = mask;
369	memset(p->mask, 0xff, indices);
370
371	p->value = p->mask + indices;
372	memset(p->value, 0, indices);
373
374	p->indices = indices;
375	p->default_index = default_index;
376	p->set_tc_index = RTA_GET_FLAG(tb[TCA_DSMARK_SET_TC_INDEX-1]);
377
378	p->q = qdisc_create_dflt(sch->dev, &pfifo_qdisc_ops, sch->handle);
379	if (p->q == NULL)
380		p->q = &noop_qdisc;
381
382	DPRINTK("dsmark_init: qdisc %p\n", p->q);
383
384	err = 0;
385errout:
386rtattr_failure:
387	return err;
388}
389
390static void dsmark_reset(struct Qdisc *sch)
391{
392	struct dsmark_qdisc_data *p = PRIV(sch);
393
394	DPRINTK("dsmark_reset(sch %p,[qdisc %p])\n", sch, p);
395	qdisc_reset(p->q);
396	sch->q.qlen = 0;
397}
398
399static void dsmark_destroy(struct Qdisc *sch)
400{
401	struct dsmark_qdisc_data *p = PRIV(sch);
402
403	DPRINTK("dsmark_destroy(sch %p,[qdisc %p])\n", sch, p);
404
405	tcf_destroy_chain(p->filter_list);
406	qdisc_destroy(p->q);
407	kfree(p->mask);
408}
409
410static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
411			     struct sk_buff *skb, struct tcmsg *tcm)
412{
413	struct dsmark_qdisc_data *p = PRIV(sch);
414	struct rtattr *opts = NULL;
415
416	DPRINTK("dsmark_dump_class(sch %p,[qdisc %p],class %ld\n", sch, p, cl);
417
418	if (!dsmark_valid_index(p, cl))
419		return -EINVAL;
420
421	tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl-1);
422	tcm->tcm_info = p->q->handle;
423
424	opts = RTA_NEST(skb, TCA_OPTIONS);
425	RTA_PUT_U8(skb,TCA_DSMARK_MASK, p->mask[cl-1]);
426	RTA_PUT_U8(skb,TCA_DSMARK_VALUE, p->value[cl-1]);
427
428	return RTA_NEST_END(skb, opts);
429
430rtattr_failure:
431	return RTA_NEST_CANCEL(skb, opts);
432}
433
434static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
435{
436	struct dsmark_qdisc_data *p = PRIV(sch);
437	struct rtattr *opts = NULL;
438
439	opts = RTA_NEST(skb, TCA_OPTIONS);
440	RTA_PUT_U16(skb, TCA_DSMARK_INDICES, p->indices);
441
442	if (p->default_index != NO_DEFAULT_INDEX)
443		RTA_PUT_U16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index);
444
445	if (p->set_tc_index)
446		RTA_PUT_FLAG(skb, TCA_DSMARK_SET_TC_INDEX);
447
448	return RTA_NEST_END(skb, opts);
449
450rtattr_failure:
451	return RTA_NEST_CANCEL(skb, opts);
452}
453
454static struct Qdisc_class_ops dsmark_class_ops = {
455	.graft		=	dsmark_graft,
456	.leaf		=	dsmark_leaf,
457	.get		=	dsmark_get,
458	.put		=	dsmark_put,
459	.change		=	dsmark_change,
460	.delete		=	dsmark_delete,
461	.walk		=	dsmark_walk,
462	.tcf_chain	=	dsmark_find_tcf,
463	.bind_tcf	=	dsmark_bind_filter,
464	.unbind_tcf	=	dsmark_put,
465	.dump		=	dsmark_dump_class,
466};
467
468static struct Qdisc_ops dsmark_qdisc_ops = {
469	.next		=	NULL,
470	.cl_ops		=	&dsmark_class_ops,
471	.id		=	"dsmark",
472	.priv_size	=	sizeof(struct dsmark_qdisc_data),
473	.enqueue	=	dsmark_enqueue,
474	.dequeue	=	dsmark_dequeue,
475	.requeue	=	dsmark_requeue,
476	.drop		=	dsmark_drop,
477	.init		=	dsmark_init,
478	.reset		=	dsmark_reset,
479	.destroy	=	dsmark_destroy,
480	.change		=	NULL,
481	.dump		=	dsmark_dump,
482	.owner		=	THIS_MODULE,
483};
484
485static int __init dsmark_module_init(void)
486{
487	return register_qdisc(&dsmark_qdisc_ops);
488}
489
490static void __exit dsmark_module_exit(void)
491{
492	unregister_qdisc(&dsmark_qdisc_ops);
493}
494
495module_init(dsmark_module_init)
496module_exit(dsmark_module_exit)
497
498MODULE_LICENSE("GPL");
499