net: fix NULL pointer in skb_segment_list
[platform/kernel/linux-rpi.git] / net / sched / sch_dsmark.c
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
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
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
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
90 static unsigned long dsmark_find(struct Qdisc *sch, u32 classid)
91 {
92         return TC_H_MIN(classid) + 1;
93 }
94
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
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
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
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
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
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
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, NULL, 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
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
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
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
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         if (p->q)
411                 qdisc_reset(p->q);
412 }
413
414 static void dsmark_destroy(struct Qdisc *sch)
415 {
416         struct dsmark_qdisc_data *p = qdisc_priv(sch);
417
418         pr_debug("%s(sch %p,[qdisc %p])\n", __func__, sch, p);
419
420         tcf_block_put(p->block);
421         qdisc_put(p->q);
422         if (p->mv != p->embedded)
423                 kfree(p->mv);
424 }
425
426 static int dsmark_dump_class(struct Qdisc *sch, unsigned long cl,
427                              struct sk_buff *skb, struct tcmsg *tcm)
428 {
429         struct dsmark_qdisc_data *p = qdisc_priv(sch);
430         struct nlattr *opts = NULL;
431
432         pr_debug("%s(sch %p,[qdisc %p],class %ld\n", __func__, sch, p, cl);
433
434         if (!dsmark_valid_index(p, cl))
435                 return -EINVAL;
436
437         tcm->tcm_handle = TC_H_MAKE(TC_H_MAJ(sch->handle), cl - 1);
438         tcm->tcm_info = p->q->handle;
439
440         opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
441         if (opts == NULL)
442                 goto nla_put_failure;
443         if (nla_put_u8(skb, TCA_DSMARK_MASK, p->mv[cl - 1].mask) ||
444             nla_put_u8(skb, TCA_DSMARK_VALUE, p->mv[cl - 1].value))
445                 goto nla_put_failure;
446
447         return nla_nest_end(skb, opts);
448
449 nla_put_failure:
450         nla_nest_cancel(skb, opts);
451         return -EMSGSIZE;
452 }
453
454 static int dsmark_dump(struct Qdisc *sch, struct sk_buff *skb)
455 {
456         struct dsmark_qdisc_data *p = qdisc_priv(sch);
457         struct nlattr *opts = NULL;
458
459         opts = nla_nest_start_noflag(skb, TCA_OPTIONS);
460         if (opts == NULL)
461                 goto nla_put_failure;
462         if (nla_put_u16(skb, TCA_DSMARK_INDICES, p->indices))
463                 goto nla_put_failure;
464
465         if (p->default_index != NO_DEFAULT_INDEX &&
466             nla_put_u16(skb, TCA_DSMARK_DEFAULT_INDEX, p->default_index))
467                 goto nla_put_failure;
468
469         if (p->set_tc_index &&
470             nla_put_flag(skb, TCA_DSMARK_SET_TC_INDEX))
471                 goto nla_put_failure;
472
473         return nla_nest_end(skb, opts);
474
475 nla_put_failure:
476         nla_nest_cancel(skb, opts);
477         return -EMSGSIZE;
478 }
479
480 static const struct Qdisc_class_ops dsmark_class_ops = {
481         .graft          =       dsmark_graft,
482         .leaf           =       dsmark_leaf,
483         .find           =       dsmark_find,
484         .change         =       dsmark_change,
485         .delete         =       dsmark_delete,
486         .walk           =       dsmark_walk,
487         .tcf_block      =       dsmark_tcf_block,
488         .bind_tcf       =       dsmark_bind_filter,
489         .unbind_tcf     =       dsmark_unbind_filter,
490         .dump           =       dsmark_dump_class,
491 };
492
493 static struct Qdisc_ops dsmark_qdisc_ops __read_mostly = {
494         .next           =       NULL,
495         .cl_ops         =       &dsmark_class_ops,
496         .id             =       "dsmark",
497         .priv_size      =       sizeof(struct dsmark_qdisc_data),
498         .enqueue        =       dsmark_enqueue,
499         .dequeue        =       dsmark_dequeue,
500         .peek           =       dsmark_peek,
501         .init           =       dsmark_init,
502         .reset          =       dsmark_reset,
503         .destroy        =       dsmark_destroy,
504         .change         =       NULL,
505         .dump           =       dsmark_dump,
506         .owner          =       THIS_MODULE,
507 };
508
509 static int __init dsmark_module_init(void)
510 {
511         return register_qdisc(&dsmark_qdisc_ops);
512 }
513
514 static void __exit dsmark_module_exit(void)
515 {
516         unregister_qdisc(&dsmark_qdisc_ops);
517 }
518
519 module_init(dsmark_module_init)
520 module_exit(dsmark_module_exit)
521
522 MODULE_LICENSE("GPL");