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/slab.h>
9 #include <linux/types.h>
10 #include <linux/string.h>
11 #include <linux/errno.h>
12 #include <linux/skbuff.h>
13 #include <linux/rtnetlink.h>
14 #include <linux/bitops.h>
15 #include <net/pkt_sched.h>
16 #include <net/dsfield.h>
17 #include <net/inet_ecn.h>
18 #include <asm/byteorder.h>
19
20 /*
21 * classid class marking
22 * ------- ----- -------
23 * n/a 0 n/a
24 * x:0 1 use entry [0]
25 * ... ... ...
26 * x:y y>0 y+1 use entry [y]
27 * ... ... ...
28 * x:indices-1 indices use entry [indices-1]
29 * ... ... ...
30 * x:y y+1 use entry [y & (indices-1)]
31 * ... ... ...
32 * 0xffff 0x10000 use entry [indices-1]
33 */
34
35
36 #define NO_DEFAULT_INDEX (1 << 16)
37
38 struct mask_value {
39 u8 mask;
40 u8 value;
41 };
42
43 struct dsmark_qdisc_data {
44 struct Qdisc *q;
45 struct tcf_proto __rcu *filter_list;
46 struct mask_value *mv;
47 u16 indices;
48 u8 set_tc_index;
49 u32 default_index; /* index range is 0...0xffff */
50 #define DSMARK_EMBEDDED_SZ 16
51 struct mask_value embedded[DSMARK_EMBEDDED_SZ];
52 };
53
dsmark_valid_index(struct dsmark_qdisc_data * p,u16 index)54 static inline int dsmark_valid_index(struct dsmark_qdisc_data *p, u16 index)
55 {
56 return index <= p->indices && index > 0;
57 }
58
59 /* ------------------------- Class/flow operations ------------------------- */
60
dsmark_graft(struct Qdisc * sch,unsigned long arg,struct Qdisc * new,struct Qdisc ** old)61 static int dsmark_graft(struct Qdisc *sch, unsigned long arg,
62 struct Qdisc *new, struct Qdisc **old)
63 {
64 struct dsmark_qdisc_data *p = qdisc_priv(sch);
65
66 pr_debug("%s(sch %p,[qdisc %p],new %p,old %p)\n",
67 __func__, sch, p, new, old);
68
69 if (new == NULL) {
70 new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
71 sch->handle);
72 if (new == NULL)
73 new = &noop_qdisc;
74 }
75
76 *old = qdisc_replace(sch, new, &p->q);
77 return 0;
78 }
79
dsmark_leaf(struct Qdisc * sch,unsigned long arg)80 static struct Qdisc *dsmark_leaf(struct Qdisc *sch, unsigned long arg)
81 {
82 struct dsmark_qdisc_data *p = qdisc_priv(sch);
83 return p->q;
84 }
85
dsmark_get(struct Qdisc * sch,u32 classid)86 static unsigned long dsmark_get(struct Qdisc *sch, u32 classid)
87 {
88 pr_debug("%s(sch %p,[qdisc %p],classid %x)\n",
89 __func__, sch, qdisc_priv(sch), classid);
90
91 return TC_H_MIN(classid) + 1;
92 }
93
dsmark_bind_filter(struct Qdisc * sch,unsigned long parent,u32 classid)94 static unsigned long dsmark_bind_filter(struct Qdisc *sch,
95 unsigned long parent, u32 classid)
96 {
97 return dsmark_get(sch, classid);
98 }
99
dsmark_put(struct Qdisc * sch,unsigned long cl)100 static void dsmark_put(struct Qdisc *sch, unsigned long cl)
101 {
102 }
103
104 static const struct nla_policy dsmark_policy[TCA_DSMARK_MAX + 1] = {
105 [TCA_DSMARK_INDICES] = { .type = NLA_U16 },
106 [TCA_DSMARK_DEFAULT_INDEX] = { .type = NLA_U16 },
107 [TCA_DSMARK_SET_TC_INDEX] = { .type = NLA_FLAG },
108 [TCA_DSMARK_MASK] = { .type = NLA_U8 },
109 [TCA_DSMARK_VALUE] = { .type = NLA_U8 },
110 };
111
dsmark_change(struct Qdisc * sch,u32 classid,u32 parent,struct nlattr ** tca,unsigned long * arg)112 static int dsmark_change(struct Qdisc *sch, u32 classid, u32 parent,
113 struct nlattr **tca, unsigned long *arg)
114 {
115 struct dsmark_qdisc_data *p = qdisc_priv(sch);
116 struct nlattr *opt = tca[TCA_OPTIONS];
117 struct nlattr *tb[TCA_DSMARK_MAX + 1];
118 int err = -EINVAL;
119
120 pr_debug("%s(sch %p,[qdisc %p],classid %x,parent %x), arg 0x%lx\n",
121 __func__, sch, p, classid, parent, *arg);
122
123 if (!dsmark_valid_index(p, *arg)) {
124 err = -ENOENT;
125 goto errout;
126 }
127
128 if (!opt)
129 goto errout;
130
131 err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy);
132 if (err < 0)
133 goto errout;
134
135 if (tb[TCA_DSMARK_VALUE])
136 p->mv[*arg - 1].value = nla_get_u8(tb[TCA_DSMARK_VALUE]);
137
138 if (tb[TCA_DSMARK_MASK])
139 p->mv[*arg - 1].mask = nla_get_u8(tb[TCA_DSMARK_MASK]);
140
141 err = 0;
142
143 errout:
144 return err;
145 }
146
dsmark_delete(struct Qdisc * sch,unsigned long arg)147 static int dsmark_delete(struct Qdisc *sch, unsigned long arg)
148 {
149 struct dsmark_qdisc_data *p = qdisc_priv(sch);
150
151 if (!dsmark_valid_index(p, arg))
152 return -EINVAL;
153
154 p->mv[arg - 1].mask = 0xff;
155 p->mv[arg - 1].value = 0;
156
157 return 0;
158 }
159
dsmark_walk(struct Qdisc * sch,struct qdisc_walker * walker)160 static void dsmark_walk(struct Qdisc *sch, struct qdisc_walker *walker)
161 {
162 struct dsmark_qdisc_data *p = qdisc_priv(sch);
163 int i;
164
165 pr_debug("%s(sch %p,[qdisc %p],walker %p)\n",
166 __func__, sch, p, walker);
167
168 if (walker->stop)
169 return;
170
171 for (i = 0; i < p->indices; i++) {
172 if (p->mv[i].mask == 0xff && !p->mv[i].value)
173 goto ignore;
174 if (walker->count >= walker->skip) {
175 if (walker->fn(sch, i + 1, walker) < 0) {
176 walker->stop = 1;
177 break;
178 }
179 }
180 ignore:
181 walker->count++;
182 }
183 }
184
dsmark_find_tcf(struct Qdisc * sch,unsigned long cl)185 static inline struct tcf_proto __rcu **dsmark_find_tcf(struct Qdisc *sch,
186 unsigned long cl)
187 {
188 struct dsmark_qdisc_data *p = qdisc_priv(sch);
189 return &p->filter_list;
190 }
191
192 /* --------------------------- Qdisc operations ---------------------------- */
193
dsmark_enqueue(struct sk_buff * skb,struct Qdisc * sch)194 static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch)
195 {
196 struct dsmark_qdisc_data *p = qdisc_priv(sch);
197 int err;
198
199 pr_debug("%s(skb %p,sch %p,[qdisc %p])\n", __func__, skb, sch, p);
200
201 if (p->set_tc_index) {
202 switch (tc_skb_protocol(skb)) {
203 case htons(ETH_P_IP):
204 if (skb_cow_head(skb, sizeof(struct iphdr)))
205 goto drop;
206
207 skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
208 & ~INET_ECN_MASK;
209 break;
210
211 case htons(ETH_P_IPV6):
212 if (skb_cow_head(skb, sizeof(struct ipv6hdr)))
213 goto drop;
214
215 skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
216 & ~INET_ECN_MASK;
217 break;
218 default:
219 skb->tc_index = 0;
220 break;
221 }
222 }
223
224 if (TC_H_MAJ(skb->priority) == sch->handle)
225 skb->tc_index = TC_H_MIN(skb->priority);
226 else {
227 struct tcf_result res;
228 struct tcf_proto *fl = rcu_dereference_bh(p->filter_list);
229 int result = tc_classify(skb, fl, &res, false);
230
231 pr_debug("result %d class 0x%04x\n", result, res.classid);
232
233 switch (result) {
234 #ifdef CONFIG_NET_CLS_ACT
235 case TC_ACT_QUEUED:
236 case TC_ACT_STOLEN:
237 kfree_skb(skb);
238 return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
239
240 case TC_ACT_SHOT:
241 goto drop;
242 #endif
243 case TC_ACT_OK:
244 skb->tc_index = TC_H_MIN(res.classid);
245 break;
246
247 default:
248 if (p->default_index != NO_DEFAULT_INDEX)
249 skb->tc_index = p->default_index;
250 break;
251 }
252 }
253
254 err = qdisc_enqueue(skb, p->q);
255 if (err != NET_XMIT_SUCCESS) {
256 if (net_xmit_drop_count(err))
257 qdisc_qstats_drop(sch);
258 return err;
259 }
260
261 qdisc_qstats_backlog_inc(sch, skb);
262 sch->q.qlen++;
263
264 return NET_XMIT_SUCCESS;
265
266 drop:
267 qdisc_drop(skb, sch);
268 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
269 }
270
dsmark_dequeue(struct Qdisc * sch)271 static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
272 {
273 struct dsmark_qdisc_data *p = qdisc_priv(sch);
274 struct sk_buff *skb;
275 u32 index;
276
277 pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
278
279 skb = p->q->ops->dequeue(p->q);
280 if (skb == NULL)
281 return NULL;
282
283 qdisc_bstats_update(sch, skb);
284 qdisc_qstats_backlog_dec(sch, skb);
285 sch->q.qlen--;
286
287 index = skb->tc_index & (p->indices - 1);
288 pr_debug("index %d->%d\n", skb->tc_index, index);
289
290 switch (tc_skb_protocol(skb)) {
291 case htons(ETH_P_IP):
292 ipv4_change_dsfield(ip_hdr(skb), p->mv[index].mask,
293 p->mv[index].value);
294 break;
295 case htons(ETH_P_IPV6):
296 ipv6_change_dsfield(ipv6_hdr(skb), p->mv[index].mask,
297 p->mv[index].value);
298 break;
299 default:
300 /*
301 * Only complain if a change was actually attempted.
302 * This way, we can send non-IP traffic through dsmark
303 * and don't need yet another qdisc as a bypass.
304 */
305 if (p->mv[index].mask != 0xff || p->mv[index].value)
306 pr_warn("%s: unsupported protocol %d\n",
307 __func__, ntohs(tc_skb_protocol(skb)));
308 break;
309 }
310
311 return skb;
312 }
313
dsmark_peek(struct Qdisc * sch)314 static struct sk_buff *dsmark_peek(struct Qdisc *sch)
315 {
316 struct dsmark_qdisc_data *p = qdisc_priv(sch);
317
318 pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
319
320 return p->q->ops->peek(p->q);
321 }
322
dsmark_drop(struct Qdisc * sch)323 static unsigned int dsmark_drop(struct Qdisc *sch)
324 {
325 struct dsmark_qdisc_data *p = qdisc_priv(sch);
326 unsigned int len;
327
328 pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
329
330 if (p->q->ops->drop == NULL)
331 return 0;
332
333 len = p->q->ops->drop(p->q);
334 if (len)
335 sch->q.qlen--;
336
337 return len;
338 }
339
dsmark_init(struct Qdisc * sch,struct nlattr * opt)340 static int dsmark_init(struct Qdisc *sch, struct nlattr *opt)
341 {
342 struct dsmark_qdisc_data *p = qdisc_priv(sch);
343 struct nlattr *tb[TCA_DSMARK_MAX + 1];
344 int err = -EINVAL;
345 u32 default_index = NO_DEFAULT_INDEX;
346 u16 indices;
347 int i;
348
349 pr_debug("%s(sch %p,[qdisc %p],opt %p)\n", __func__, sch, p, opt);
350
351 if (!opt)
352 goto errout;
353
354 err = nla_parse_nested(tb, TCA_DSMARK_MAX, opt, dsmark_policy);
355 if (err < 0)
356 goto errout;
357
358 err = -EINVAL;
359 indices = nla_get_u16(tb[TCA_DSMARK_INDICES]);
360
361 if (hweight32(indices) != 1)
362 goto errout;
363
364 if (tb[TCA_DSMARK_DEFAULT_INDEX])
365 default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);
366
367 if (indices <= DSMARK_EMBEDDED_SZ)
368 p->mv = p->embedded;
369 else
370 p->mv = kmalloc_array(indices, sizeof(*p->mv), GFP_KERNEL);
371 if (!p->mv) {
372 err = -ENOMEM;
373 goto errout;
374 }
375 for (i = 0; i < indices; i++) {
376 p->mv[i].mask = 0xff;
377 p->mv[i].value = 0;
378 }
379 p->indices = indices;
380 p->default_index = default_index;
381 p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);
382
383 p->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, sch->handle);
384 if (p->q == NULL)
385 p->q = &noop_qdisc;
386
387 pr_debug("%s: qdisc %p\n", __func__, p->q);
388
389 err = 0;
390 errout:
391 return err;
392 }
393
dsmark_reset(struct Qdisc * sch)394 static void dsmark_reset(struct Qdisc *sch)
395 {
396 struct dsmark_qdisc_data *p = qdisc_priv(sch);
397
398 pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
399 qdisc_reset(p->q);
400 sch->qstats.backlog = 0;
401 sch->q.qlen = 0;
402 }
403
dsmark_destroy(struct Qdisc * sch)404 static void dsmark_destroy(struct Qdisc *sch)
405 {
406 struct dsmark_qdisc_data *p = qdisc_priv(sch);
407
408 pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
409
410 tcf_destroy_chain(&p->filter_list);
411 qdisc_destroy(p->q);
412 if (p->mv != p->embedded)
413 kfree(p->mv);
414 }
415
dsmark_dump_class(struct Qdisc * sch,unsigned long cl,struct sk_buff * skb,struct tcmsg * tcm)416 static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
417 struct sk_buff *skb, struct tcmsg *tcm)
418 {
419 struct dsmark_qdisc_data *p = qdisc_priv(sch);
420 struct nlattr *opts = NULL;
421
422 pr_debug("%s(sch %p,[qdisc %p],class %ld\n", __func__, sch, p, cl);
423
424 if (!dsmark_valid_index(p, cl))
425 return -EINVAL;
426
427 tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl - 1);
428 tcm->tcm_info = p->q->handle;
429
430 opts = nla_nest_start(skb, TCA_OPTIONS);
431 if (opts == NULL)
432 goto nla_put_failure;
433 if (nla_put_u8(skb, TCA_DSMARK_MASK, p->mv[cl - 1].mask) ||
434 nla_put_u8(skb, TCA_DSMARK_VALUE, p->mv[cl - 1].value))
435 goto nla_put_failure;
436
437 return nla_nest_end(skb, opts);
438
439 nla_put_failure:
440 nla_nest_cancel(skb, opts);
441 return -EMSGSIZE;
442 }
443
dsmark_dump(struct Qdisc * sch,struct sk_buff * skb)444 static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
445 {
446 struct dsmark_qdisc_data *p = qdisc_priv(sch);
447 struct nlattr *opts = NULL;
448
449 opts = nla_nest_start(skb, TCA_OPTIONS);
450 if (opts == NULL)
451 goto nla_put_failure;
452 if (nla_put_u16(skb, TCA_DSMARK_INDICES, p->indices))
453 goto nla_put_failure;
454
455 if (p->default_index != NO_DEFAULT_INDEX &&
456 nla_put_u16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index))
457 goto nla_put_failure;
458
459 if (p->set_tc_index &&
460 nla_put_flag(skb, TCA_DSMARK_SET_TC_INDEX))
461 goto nla_put_failure;
462
463 return nla_nest_end(skb, opts);
464
465 nla_put_failure:
466 nla_nest_cancel(skb, opts);
467 return -EMSGSIZE;
468 }
469
470 static const struct Qdisc_class_ops dsmark_class_ops = {
471 .graft = dsmark_graft,
472 .leaf = dsmark_leaf,
473 .get = dsmark_get,
474 .put = dsmark_put,
475 .change = dsmark_change,
476 .delete = dsmark_delete,
477 .walk = dsmark_walk,
478 .tcf_chain = dsmark_find_tcf,
479 .bind_tcf = dsmark_bind_filter,
480 .unbind_tcf = dsmark_put,
481 .dump = dsmark_dump_class,
482 };
483
484 static struct Qdisc_ops dsmark_qdisc_ops __read_mostly = {
485 .next = NULL,
486 .cl_ops = &dsmark_class_ops,
487 .id = "dsmark",
488 .priv_size = sizeof(struct dsmark_qdisc_data),
489 .enqueue = dsmark_enqueue,
490 .dequeue = dsmark_dequeue,
491 .peek = dsmark_peek,
492 .drop = dsmark_drop,
493 .init = dsmark_init,
494 .reset = dsmark_reset,
495 .destroy = dsmark_destroy,
496 .change = NULL,
497 .dump = dsmark_dump,
498 .owner = THIS_MODULE,
499 };
500
dsmark_module_init(void)501 static int __init dsmark_module_init(void)
502 {
503 return register_qdisc(&dsmark_qdisc_ops);
504 }
505
dsmark_module_exit(void)506 static void __exit dsmark_module_exit(void)
507 {
508 unregister_qdisc(&dsmark_qdisc_ops);
509 }
510
511 module_init(dsmark_module_init)
512 module_exit(dsmark_module_exit)
513
514 MODULE_LICENSE("GPL");
515