1 // SPDX-License-Identifier: GPL-2.0-only
2 /* net/sched/sch_dsmark.c - Differentiated Services field marker */
3
4 /* Written 1998-2000 by Werner Almesberger, EPFL ICA */
5
6
7 #include <linux/module.h>
8 #include <linux/init.h>
9 #include <linux/slab.h>
10 #include <linux/types.h>
11 #include <linux/string.h>
12 #include <linux/errno.h>
13 #include <linux/skbuff.h>
14 #include <linux/rtnetlink.h>
15 #include <linux/bitops.h>
16 #include <net/pkt_sched.h>
17 #include <net/pkt_cls.h>
18 #include <net/dsfield.h>
19 #include <net/inet_ecn.h>
20 #include <asm/byteorder.h>
21
22 /*
23 * classid class marking
24 * ------- ----- -------
25 * n/a 0 n/a
26 * x:0 1 use entry [0]
27 * ... ... ...
28 * x:y y>0 y+1 use entry [y]
29 * ... ... ...
30 * x:indices-1 indices use entry [indices-1]
31 * ... ... ...
32 * x:y y+1 use entry [y & (indices-1)]
33 * ... ... ...
34 * 0xffff 0x10000 use entry [indices-1]
35 */
36
37
38 #define NO_DEFAULT_INDEX (1 << 16)
39
40 struct mask_value {
41 u8 mask;
42 u8 value;
43 };
44
45 struct dsmark_qdisc_data {
46 struct Qdisc *q;
47 struct tcf_proto __rcu *filter_list;
48 struct tcf_block *block;
49 struct mask_value *mv;
50 u16 indices;
51 u8 set_tc_index;
52 u32 default_index; /* index range is 0...0xffff */
53 #define DSMARK_EMBEDDED_SZ 16
54 struct mask_value embedded[DSMARK_EMBEDDED_SZ];
55 };
56
dsmark_valid_index(struct dsmark_qdisc_data * p,u16 index)57 static inline int dsmark_valid_index(struct dsmark_qdisc_data *p, u16 index)
58 {
59 return index <= p->indices && index > 0;
60 }
61
62 /* ------------------------- Class/flow operations ------------------------- */
63
dsmark_graft(struct Qdisc * sch,unsigned long arg,struct Qdisc * new,struct Qdisc ** old,struct netlink_ext_ack * extack)64 static int dsmark_graft(struct Qdisc *sch, unsigned long arg,
65 struct Qdisc *new, struct Qdisc **old,
66 struct netlink_ext_ack *extack)
67 {
68 struct dsmark_qdisc_data *p = qdisc_priv(sch);
69
70 pr_debug("%s(sch %p,[qdisc %p],new %p,old %p)\n",
71 __func__, sch, p, new, old);
72
73 if (new == NULL) {
74 new = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops,
75 sch->handle, NULL);
76 if (new == NULL)
77 new = &noop_qdisc;
78 }
79
80 *old = qdisc_replace(sch, new, &p->q);
81 return 0;
82 }
83
dsmark_leaf(struct Qdisc * sch,unsigned long arg)84 static struct Qdisc *dsmark_leaf(struct Qdisc *sch, unsigned long arg)
85 {
86 struct dsmark_qdisc_data *p = qdisc_priv(sch);
87 return p->q;
88 }
89
dsmark_find(struct Qdisc * sch,u32 classid)90 static unsigned long dsmark_find(struct Qdisc *sch, u32 classid)
91 {
92 return TC_H_MIN(classid) + 1;
93 }
94
dsmark_bind_filter(struct Qdisc * sch,unsigned long parent,u32 classid)95 static unsigned long dsmark_bind_filter(struct Qdisc *sch,
96 unsigned long parent, u32 classid)
97 {
98 pr_debug("%s(sch %p,[qdisc %p],classid %x)\n",
99 __func__, sch, qdisc_priv(sch), classid);
100
101 return dsmark_find(sch, classid);
102 }
103
dsmark_unbind_filter(struct Qdisc * sch,unsigned long cl)104 static void dsmark_unbind_filter(struct Qdisc *sch, unsigned long cl)
105 {
106 }
107
108 static const struct nla_policy dsmark_policy[TCA_DSMARK_MAX + 1] = {
109 [TCA_DSMARK_INDICES] = { .type = NLA_U16 },
110 [TCA_DSMARK_DEFAULT_INDEX] = { .type = NLA_U16 },
111 [TCA_DSMARK_SET_TC_INDEX] = { .type = NLA_FLAG },
112 [TCA_DSMARK_MASK] = { .type = NLA_U8 },
113 [TCA_DSMARK_VALUE] = { .type = NLA_U8 },
114 };
115
dsmark_change(struct Qdisc * sch,u32 classid,u32 parent,struct nlattr ** tca,unsigned long * arg,struct netlink_ext_ack * extack)116 static int dsmark_change(struct Qdisc *sch, u32 classid, u32 parent,
117 struct nlattr **tca, unsigned long *arg,
118 struct netlink_ext_ack *extack)
119 {
120 struct dsmark_qdisc_data *p = qdisc_priv(sch);
121 struct nlattr *opt = tca[TCA_OPTIONS];
122 struct nlattr *tb[TCA_DSMARK_MAX + 1];
123 int err = -EINVAL;
124
125 pr_debug("%s(sch %p,[qdisc %p],classid %x,parent %x), arg 0x%lx\n",
126 __func__, sch, p, classid, parent, *arg);
127
128 if (!dsmark_valid_index(p, *arg)) {
129 err = -ENOENT;
130 goto errout;
131 }
132
133 if (!opt)
134 goto errout;
135
136 err = nla_parse_nested_deprecated(tb, TCA_DSMARK_MAX, opt,
137 dsmark_policy, NULL);
138 if (err < 0)
139 goto errout;
140
141 if (tb[TCA_DSMARK_VALUE])
142 p->mv[*arg - 1].value = nla_get_u8(tb[TCA_DSMARK_VALUE]);
143
144 if (tb[TCA_DSMARK_MASK])
145 p->mv[*arg - 1].mask = nla_get_u8(tb[TCA_DSMARK_MASK]);
146
147 err = 0;
148
149 errout:
150 return err;
151 }
152
dsmark_delete(struct Qdisc * sch,unsigned long arg,struct netlink_ext_ack * extack)153 static int dsmark_delete(struct Qdisc *sch, unsigned long arg,
154 struct netlink_ext_ack *extack)
155 {
156 struct dsmark_qdisc_data *p = qdisc_priv(sch);
157
158 if (!dsmark_valid_index(p, arg))
159 return -EINVAL;
160
161 p->mv[arg - 1].mask = 0xff;
162 p->mv[arg - 1].value = 0;
163
164 return 0;
165 }
166
dsmark_walk(struct Qdisc * sch,struct qdisc_walker * walker)167 static void dsmark_walk(struct Qdisc *sch, struct qdisc_walker *walker)
168 {
169 struct dsmark_qdisc_data *p = qdisc_priv(sch);
170 int i;
171
172 pr_debug("%s(sch %p,[qdisc %p],walker %p)\n",
173 __func__, sch, p, walker);
174
175 if (walker->stop)
176 return;
177
178 for (i = 0; i < p->indices; i++) {
179 if (p->mv[i].mask == 0xff && !p->mv[i].value)
180 goto ignore;
181 if (walker->count >= walker->skip) {
182 if (walker->fn(sch, i + 1, walker) < 0) {
183 walker->stop = 1;
184 break;
185 }
186 }
187 ignore:
188 walker->count++;
189 }
190 }
191
dsmark_tcf_block(struct Qdisc * sch,unsigned long cl,struct netlink_ext_ack * extack)192 static struct tcf_block *dsmark_tcf_block(struct Qdisc *sch, unsigned long cl,
193 struct netlink_ext_ack *extack)
194 {
195 struct dsmark_qdisc_data *p = qdisc_priv(sch);
196
197 return p->block;
198 }
199
200 /* --------------------------- Qdisc operations ---------------------------- */
201
dsmark_enqueue(struct sk_buff * skb,struct Qdisc * sch,struct sk_buff ** to_free)202 static int dsmark_enqueue(struct sk_buff *skb, struct Qdisc *sch,
203 struct sk_buff **to_free)
204 {
205 unsigned int len = qdisc_pkt_len(skb);
206 struct dsmark_qdisc_data *p = qdisc_priv(sch);
207 int err;
208
209 pr_debug("%s(skb %p,sch %p,[qdisc %p])\n", __func__, skb, sch, p);
210
211 if (p->set_tc_index) {
212 int wlen = skb_network_offset(skb);
213
214 switch (skb_protocol(skb, true)) {
215 case htons(ETH_P_IP):
216 wlen += sizeof(struct iphdr);
217 if (!pskb_may_pull(skb, wlen) ||
218 skb_try_make_writable(skb, wlen))
219 goto drop;
220
221 skb->tc_index = ipv4_get_dsfield(ip_hdr(skb))
222 & ~INET_ECN_MASK;
223 break;
224
225 case htons(ETH_P_IPV6):
226 wlen += sizeof(struct ipv6hdr);
227 if (!pskb_may_pull(skb, wlen) ||
228 skb_try_make_writable(skb, wlen))
229 goto drop;
230
231 skb->tc_index = ipv6_get_dsfield(ipv6_hdr(skb))
232 & ~INET_ECN_MASK;
233 break;
234 default:
235 skb->tc_index = 0;
236 break;
237 }
238 }
239
240 if (TC_H_MAJ(skb->priority) == sch->handle)
241 skb->tc_index = TC_H_MIN(skb->priority);
242 else {
243 struct tcf_result res;
244 struct tcf_proto *fl = rcu_dereference_bh(p->filter_list);
245 int result = tcf_classify(skb, fl, &res, false);
246
247 pr_debug("result %d class 0x%04x\n", result, res.classid);
248
249 switch (result) {
250 #ifdef CONFIG_NET_CLS_ACT
251 case TC_ACT_QUEUED:
252 case TC_ACT_STOLEN:
253 case TC_ACT_TRAP:
254 __qdisc_drop(skb, to_free);
255 return NET_XMIT_SUCCESS | __NET_XMIT_STOLEN;
256
257 case TC_ACT_SHOT:
258 goto drop;
259 #endif
260 case TC_ACT_OK:
261 skb->tc_index = TC_H_MIN(res.classid);
262 break;
263
264 default:
265 if (p->default_index != NO_DEFAULT_INDEX)
266 skb->tc_index = p->default_index;
267 break;
268 }
269 }
270
271 err = qdisc_enqueue(skb, p->q, to_free);
272 if (err != NET_XMIT_SUCCESS) {
273 if (net_xmit_drop_count(err))
274 qdisc_qstats_drop(sch);
275 return err;
276 }
277
278 sch->qstats.backlog += len;
279 sch->q.qlen++;
280
281 return NET_XMIT_SUCCESS;
282
283 drop:
284 qdisc_drop(skb, sch, to_free);
285 return NET_XMIT_SUCCESS | __NET_XMIT_BYPASS;
286 }
287
dsmark_dequeue(struct Qdisc * sch)288 static struct sk_buff *dsmark_dequeue(struct Qdisc *sch)
289 {
290 struct dsmark_qdisc_data *p = qdisc_priv(sch);
291 struct sk_buff *skb;
292 u32 index;
293
294 pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
295
296 skb = qdisc_dequeue_peeked(p->q);
297 if (skb == NULL)
298 return NULL;
299
300 qdisc_bstats_update(sch, skb);
301 qdisc_qstats_backlog_dec(sch, skb);
302 sch->q.qlen--;
303
304 index = skb->tc_index & (p->indices - 1);
305 pr_debug("index %d->%d\n", skb->tc_index, index);
306
307 switch (skb_protocol(skb, true)) {
308 case htons(ETH_P_IP):
309 ipv4_change_dsfield(ip_hdr(skb), p->mv[index].mask,
310 p->mv[index].value);
311 break;
312 case htons(ETH_P_IPV6):
313 ipv6_change_dsfield(ipv6_hdr(skb), p->mv[index].mask,
314 p->mv[index].value);
315 break;
316 default:
317 /*
318 * Only complain if a change was actually attempted.
319 * This way, we can send non-IP traffic through dsmark
320 * and don't need yet another qdisc as a bypass.
321 */
322 if (p->mv[index].mask != 0xff || p->mv[index].value)
323 pr_warn("%s: unsupported protocol %d\n",
324 __func__, ntohs(skb_protocol(skb, true)));
325 break;
326 }
327
328 return skb;
329 }
330
dsmark_peek(struct Qdisc * sch)331 static struct sk_buff *dsmark_peek(struct Qdisc *sch)
332 {
333 struct dsmark_qdisc_data *p = qdisc_priv(sch);
334
335 pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
336
337 return p->q->ops->peek(p->q);
338 }
339
dsmark_init(struct Qdisc * sch,struct nlattr * opt,struct netlink_ext_ack * extack)340 static int dsmark_init(struct Qdisc *sch, struct nlattr *opt,
341 struct netlink_ext_ack *extack)
342 {
343 struct dsmark_qdisc_data *p = qdisc_priv(sch);
344 struct nlattr *tb[TCA_DSMARK_MAX + 1];
345 int err = -EINVAL;
346 u32 default_index = NO_DEFAULT_INDEX;
347 u16 indices;
348 int i;
349
350 pr_debug("%s(sch %p,[qdisc %p],opt %p)\n", __func__, sch, p, opt);
351
352 if (!opt)
353 goto errout;
354
355 err = tcf_block_get(&p->block, &p->filter_list, sch, extack);
356 if (err)
357 return err;
358
359 err = nla_parse_nested_deprecated(tb, TCA_DSMARK_MAX, opt,
360 dsmark_policy, NULL);
361 if (err < 0)
362 goto errout;
363
364 err = -EINVAL;
365 if (!tb[TCA_DSMARK_INDICES])
366 goto errout;
367 indices = nla_get_u16(tb[TCA_DSMARK_INDICES]);
368
369 if (hweight32(indices) != 1)
370 goto errout;
371
372 if (tb[TCA_DSMARK_DEFAULT_INDEX])
373 default_index = nla_get_u16(tb[TCA_DSMARK_DEFAULT_INDEX]);
374
375 if (indices <= DSMARK_EMBEDDED_SZ)
376 p->mv = p->embedded;
377 else
378 p->mv = kmalloc_array(indices, sizeof(*p->mv), GFP_KERNEL);
379 if (!p->mv) {
380 err = -ENOMEM;
381 goto errout;
382 }
383 for (i = 0; i < indices; i++) {
384 p->mv[i].mask = 0xff;
385 p->mv[i].value = 0;
386 }
387 p->indices = indices;
388 p->default_index = default_index;
389 p->set_tc_index = nla_get_flag(tb[TCA_DSMARK_SET_TC_INDEX]);
390
391 p->q = qdisc_create_dflt(sch->dev_queue, &pfifo_qdisc_ops, sch->handle,
392 NULL);
393 if (p->q == NULL)
394 p->q = &noop_qdisc;
395 else
396 qdisc_hash_add(p->q, true);
397
398 pr_debug("%s: qdisc %p\n", __func__, p->q);
399
400 err = 0;
401 errout:
402 return err;
403 }
404
dsmark_reset(struct Qdisc * sch)405 static void dsmark_reset(struct Qdisc *sch)
406 {
407 struct dsmark_qdisc_data *p = qdisc_priv(sch);
408
409 pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
410 qdisc_reset(p->q);
411 sch->qstats.backlog = 0;
412 sch->q.qlen = 0;
413 }
414
dsmark_destroy(struct Qdisc * sch)415 static void dsmark_destroy(struct Qdisc *sch)
416 {
417 struct dsmark_qdisc_data *p = qdisc_priv(sch);
418
419 pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
420
421 tcf_block_put(p->block);
422 qdisc_put(p->q);
423 if (p->mv != p->embedded)
424 kfree(p->mv);
425 }
426
dsmark_dump_class(struct Qdisc * sch,unsigned long cl,struct sk_buff * skb,struct tcmsg * tcm)427 static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
428 struct sk_buff *skb, struct tcmsg *tcm)
429 {
430 struct dsmark_qdisc_data *p = qdisc_priv(sch);
431 struct nlattr *opts = NULL;
432
433 pr_debug("%s(sch %p,[qdisc %p],class %ld\n", __func__, sch, p, cl);
434
435 if (!dsmark_valid_index(p, cl))
436 return -EINVAL;
437
438 tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl - 1);
439 tcm->tcm_info = p->q->handle;
440
441 opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
442 if (opts == NULL)
443 goto nla_put_failure;
444 if (nla_put_u8(skb, TCA_DSMARK_MASK, p->mv[cl - 1].mask) ||
445 nla_put_u8(skb, TCA_DSMARK_VALUE, p->mv[cl - 1].value))
446 goto nla_put_failure;
447
448 return nla_nest_end(skb, opts);
449
450 nla_put_failure:
451 nla_nest_cancel(skb, opts);
452 return -EMSGSIZE;
453 }
454
dsmark_dump(struct Qdisc * sch,struct sk_buff * skb)455 static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
456 {
457 struct dsmark_qdisc_data *p = qdisc_priv(sch);
458 struct nlattr *opts = NULL;
459
460 opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
461 if (opts == NULL)
462 goto nla_put_failure;
463 if (nla_put_u16(skb, TCA_DSMARK_INDICES, p->indices))
464 goto nla_put_failure;
465
466 if (p->default_index != NO_DEFAULT_INDEX &&
467 nla_put_u16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index))
468 goto nla_put_failure;
469
470 if (p->set_tc_index &&
471 nla_put_flag(skb, TCA_DSMARK_SET_TC_INDEX))
472 goto nla_put_failure;
473
474 return nla_nest_end(skb, opts);
475
476 nla_put_failure:
477 nla_nest_cancel(skb, opts);
478 return -EMSGSIZE;
479 }
480
481 static const struct Qdisc_class_ops dsmark_class_ops = {
482 .graft = dsmark_graft,
483 .leaf = dsmark_leaf,
484 .find = dsmark_find,
485 .change = dsmark_change,
486 .delete = dsmark_delete,
487 .walk = dsmark_walk,
488 .tcf_block = dsmark_tcf_block,
489 .bind_tcf = dsmark_bind_filter,
490 .unbind_tcf = dsmark_unbind_filter,
491 .dump = dsmark_dump_class,
492 };
493
494 static struct Qdisc_ops dsmark_qdisc_ops __read_mostly = {
495 .next = NULL,
496 .cl_ops = &dsmark_class_ops,
497 .id = "dsmark",
498 .priv_size = sizeof(struct dsmark_qdisc_data),
499 .enqueue = dsmark_enqueue,
500 .dequeue = dsmark_dequeue,
501 .peek = dsmark_peek,
502 .init = dsmark_init,
503 .reset = dsmark_reset,
504 .destroy = dsmark_destroy,
505 .change = NULL,
506 .dump = dsmark_dump,
507 .owner = THIS_MODULE,
508 };
509
dsmark_module_init(void)510 static int __init dsmark_module_init(void)
511 {
512 return register_qdisc(&dsmark_qdisc_ops);
513 }
514
dsmark_module_exit(void)515 static void __exit dsmark_module_exit(void)
516 {
517 unregister_qdisc(&dsmark_qdisc_ops);
518 }
519
520 module_init(dsmark_module_init)
521 module_exit(dsmark_module_exit)
522
523 MODULE_LICENSE("GPL");
524