1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * net/sched/act_pedit.c Generic packet editor
4 *
5 * Authors: Jamal Hadi Salim (2002-4)
6 */
7
8 #include <linux/types.h>
9 #include <linux/kernel.h>
10 #include <linux/string.h>
11 #include <linux/errno.h>
12 #include <linux/skbuff.h>
13 #include <linux/rtnetlink.h>
14 #include <linux/module.h>
15 #include <linux/init.h>
16 #include <linux/slab.h>
17 #include <net/netlink.h>
18 #include <net/pkt_sched.h>
19 #include <linux/tc_act/tc_pedit.h>
20 #include <net/tc_act/tc_pedit.h>
21 #include <uapi/linux/tc_act/tc_pedit.h>
22 #include <net/pkt_cls.h>
23
24 static unsigned int pedit_net_id;
25 static struct tc_action_ops act_pedit_ops;
26
27 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
28 [TCA_PEDIT_PARMS] = { .len = sizeof(struct tc_pedit) },
29 [TCA_PEDIT_PARMS_EX] = { .len = sizeof(struct tc_pedit) },
30 [TCA_PEDIT_KEYS_EX] = { .type = NLA_NESTED },
31 };
32
33 static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
34 [TCA_PEDIT_KEY_EX_HTYPE] = { .type = NLA_U16 },
35 [TCA_PEDIT_KEY_EX_CMD] = { .type = NLA_U16 },
36 };
37
tcf_pedit_keys_ex_parse(struct nlattr * nla,u8 n)38 static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
39 u8 n)
40 {
41 struct tcf_pedit_key_ex *keys_ex;
42 struct tcf_pedit_key_ex *k;
43 const struct nlattr *ka;
44 int err = -EINVAL;
45 int rem;
46
47 if (!nla)
48 return NULL;
49
50 keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
51 if (!keys_ex)
52 return ERR_PTR(-ENOMEM);
53
54 k = keys_ex;
55
56 nla_for_each_nested(ka, nla, rem) {
57 struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
58
59 if (!n) {
60 err = -EINVAL;
61 goto err_out;
62 }
63 n--;
64
65 if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
66 err = -EINVAL;
67 goto err_out;
68 }
69
70 err = nla_parse_nested_deprecated(tb, TCA_PEDIT_KEY_EX_MAX,
71 ka, pedit_key_ex_policy,
72 NULL);
73 if (err)
74 goto err_out;
75
76 if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
77 !tb[TCA_PEDIT_KEY_EX_CMD]) {
78 err = -EINVAL;
79 goto err_out;
80 }
81
82 k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
83 k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
84
85 if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
86 k->cmd > TCA_PEDIT_CMD_MAX) {
87 err = -EINVAL;
88 goto err_out;
89 }
90
91 k++;
92 }
93
94 if (n) {
95 err = -EINVAL;
96 goto err_out;
97 }
98
99 return keys_ex;
100
101 err_out:
102 kfree(keys_ex);
103 return ERR_PTR(err);
104 }
105
tcf_pedit_key_ex_dump(struct sk_buff * skb,struct tcf_pedit_key_ex * keys_ex,int n)106 static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
107 struct tcf_pedit_key_ex *keys_ex, int n)
108 {
109 struct nlattr *keys_start = nla_nest_start_noflag(skb,
110 TCA_PEDIT_KEYS_EX);
111
112 if (!keys_start)
113 goto nla_failure;
114 for (; n > 0; n--) {
115 struct nlattr *key_start;
116
117 key_start = nla_nest_start_noflag(skb, TCA_PEDIT_KEY_EX);
118 if (!key_start)
119 goto nla_failure;
120
121 if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
122 nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
123 goto nla_failure;
124
125 nla_nest_end(skb, key_start);
126
127 keys_ex++;
128 }
129
130 nla_nest_end(skb, keys_start);
131
132 return 0;
133 nla_failure:
134 nla_nest_cancel(skb, keys_start);
135 return -EINVAL;
136 }
137
tcf_pedit_init(struct net * net,struct nlattr * nla,struct nlattr * est,struct tc_action ** a,int ovr,int bind,bool rtnl_held,struct tcf_proto * tp,u32 flags,struct netlink_ext_ack * extack)138 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
139 struct nlattr *est, struct tc_action **a,
140 int ovr, int bind, bool rtnl_held,
141 struct tcf_proto *tp, u32 flags,
142 struct netlink_ext_ack *extack)
143 {
144 struct tc_action_net *tn = net_generic(net, pedit_net_id);
145 struct nlattr *tb[TCA_PEDIT_MAX + 1];
146 struct tcf_chain *goto_ch = NULL;
147 struct tc_pedit_key *keys = NULL;
148 struct tcf_pedit_key_ex *keys_ex;
149 struct tc_pedit *parm;
150 struct nlattr *pattr;
151 struct tcf_pedit *p;
152 int ret = 0, err;
153 int i, ksize;
154 u32 index;
155
156 if (!nla) {
157 NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
158 return -EINVAL;
159 }
160
161 err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
162 pedit_policy, NULL);
163 if (err < 0)
164 return err;
165
166 pattr = tb[TCA_PEDIT_PARMS];
167 if (!pattr)
168 pattr = tb[TCA_PEDIT_PARMS_EX];
169 if (!pattr) {
170 NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
171 return -EINVAL;
172 }
173
174 parm = nla_data(pattr);
175 if (!parm->nkeys) {
176 NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
177 return -EINVAL;
178 }
179 ksize = parm->nkeys * sizeof(struct tc_pedit_key);
180 if (nla_len(pattr) < sizeof(*parm) + ksize) {
181 NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
182 return -EINVAL;
183 }
184
185 keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
186 if (IS_ERR(keys_ex))
187 return PTR_ERR(keys_ex);
188
189 index = parm->index;
190 err = tcf_idr_check_alloc(tn, &index, a, bind);
191 if (!err) {
192 ret = tcf_idr_create(tn, index, est, a,
193 &act_pedit_ops, bind, false, flags);
194 if (ret) {
195 tcf_idr_cleanup(tn, index);
196 goto out_free;
197 }
198 ret = ACT_P_CREATED;
199 } else if (err > 0) {
200 if (bind)
201 goto out_free;
202 if (!ovr) {
203 ret = -EEXIST;
204 goto out_release;
205 }
206 } else {
207 ret = err;
208 goto out_free;
209 }
210
211 err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
212 if (err < 0) {
213 ret = err;
214 goto out_release;
215 }
216 p = to_pedit(*a);
217 spin_lock_bh(&p->tcf_lock);
218
219 if (ret == ACT_P_CREATED ||
220 (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
221 keys = kmalloc(ksize, GFP_ATOMIC);
222 if (!keys) {
223 spin_unlock_bh(&p->tcf_lock);
224 ret = -ENOMEM;
225 goto put_chain;
226 }
227 kfree(p->tcfp_keys);
228 p->tcfp_keys = keys;
229 p->tcfp_nkeys = parm->nkeys;
230 }
231 memcpy(p->tcfp_keys, parm->keys, ksize);
232 p->tcfp_off_max_hint = 0;
233 for (i = 0; i < p->tcfp_nkeys; ++i) {
234 u32 cur = p->tcfp_keys[i].off;
235
236 /* sanitize the shift value for any later use */
237 p->tcfp_keys[i].shift = min_t(size_t, BITS_PER_TYPE(int) - 1,
238 p->tcfp_keys[i].shift);
239
240 /* The AT option can read a single byte, we can bound the actual
241 * value with uchar max.
242 */
243 cur += (0xff & p->tcfp_keys[i].offmask) >> p->tcfp_keys[i].shift;
244
245 /* Each key touches 4 bytes starting from the computed offset */
246 p->tcfp_off_max_hint = max(p->tcfp_off_max_hint, cur + 4);
247 }
248
249 p->tcfp_flags = parm->flags;
250 goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
251
252 kfree(p->tcfp_keys_ex);
253 p->tcfp_keys_ex = keys_ex;
254
255 spin_unlock_bh(&p->tcf_lock);
256 if (goto_ch)
257 tcf_chain_put_by_act(goto_ch);
258 return ret;
259
260 put_chain:
261 if (goto_ch)
262 tcf_chain_put_by_act(goto_ch);
263 out_release:
264 tcf_idr_release(*a, bind);
265 out_free:
266 kfree(keys_ex);
267 return ret;
268
269 }
270
tcf_pedit_cleanup(struct tc_action * a)271 static void tcf_pedit_cleanup(struct tc_action *a)
272 {
273 struct tcf_pedit *p = to_pedit(a);
274 struct tc_pedit_key *keys = p->tcfp_keys;
275
276 kfree(keys);
277 kfree(p->tcfp_keys_ex);
278 }
279
offset_valid(struct sk_buff * skb,int offset)280 static bool offset_valid(struct sk_buff *skb, int offset)
281 {
282 if (offset > 0 && offset > skb->len)
283 return false;
284
285 if (offset < 0 && -offset > skb_headroom(skb))
286 return false;
287
288 return true;
289 }
290
pedit_skb_hdr_offset(struct sk_buff * skb,enum pedit_header_type htype,int * hoffset)291 static int pedit_skb_hdr_offset(struct sk_buff *skb,
292 enum pedit_header_type htype, int *hoffset)
293 {
294 int ret = -EINVAL;
295
296 switch (htype) {
297 case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
298 if (skb_mac_header_was_set(skb)) {
299 *hoffset = skb_mac_offset(skb);
300 ret = 0;
301 }
302 break;
303 case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
304 case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
305 case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
306 *hoffset = skb_network_offset(skb);
307 ret = 0;
308 break;
309 case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
310 case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
311 if (skb_transport_header_was_set(skb)) {
312 *hoffset = skb_transport_offset(skb);
313 ret = 0;
314 }
315 break;
316 default:
317 ret = -EINVAL;
318 break;
319 }
320
321 return ret;
322 }
323
tcf_pedit_act(struct sk_buff * skb,const struct tc_action * a,struct tcf_result * res)324 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
325 struct tcf_result *res)
326 {
327 struct tcf_pedit *p = to_pedit(a);
328 u32 max_offset;
329 int i;
330
331 spin_lock(&p->tcf_lock);
332
333 max_offset = (skb_transport_header_was_set(skb) ?
334 skb_transport_offset(skb) :
335 skb_network_offset(skb)) +
336 p->tcfp_off_max_hint;
337 if (skb_ensure_writable(skb, min(skb->len, max_offset)))
338 goto unlock;
339
340 tcf_lastuse_update(&p->tcf_tm);
341
342 if (p->tcfp_nkeys > 0) {
343 struct tc_pedit_key *tkey = p->tcfp_keys;
344 struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
345 enum pedit_header_type htype =
346 TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
347 enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
348
349 for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
350 u32 *ptr, hdata;
351 int offset = tkey->off;
352 int hoffset;
353 u32 val;
354 int rc;
355
356 if (tkey_ex) {
357 htype = tkey_ex->htype;
358 cmd = tkey_ex->cmd;
359
360 tkey_ex++;
361 }
362
363 rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
364 if (rc) {
365 pr_info("tc action pedit bad header type specified (0x%x)\n",
366 htype);
367 goto bad;
368 }
369
370 if (tkey->offmask) {
371 u8 *d, _d;
372
373 if (!offset_valid(skb, hoffset + tkey->at)) {
374 pr_info("tc action pedit 'at' offset %d out of bounds\n",
375 hoffset + tkey->at);
376 goto bad;
377 }
378 d = skb_header_pointer(skb, hoffset + tkey->at,
379 sizeof(_d), &_d);
380 if (!d)
381 goto bad;
382 offset += (*d & tkey->offmask) >> tkey->shift;
383 }
384
385 if (offset % 4) {
386 pr_info("tc action pedit offset must be on 32 bit boundaries\n");
387 goto bad;
388 }
389
390 if (!offset_valid(skb, hoffset + offset)) {
391 pr_info("tc action pedit offset %d out of bounds\n",
392 hoffset + offset);
393 goto bad;
394 }
395
396 ptr = skb_header_pointer(skb, hoffset + offset,
397 sizeof(hdata), &hdata);
398 if (!ptr)
399 goto bad;
400 /* just do it, baby */
401 switch (cmd) {
402 case TCA_PEDIT_KEY_EX_CMD_SET:
403 val = tkey->val;
404 break;
405 case TCA_PEDIT_KEY_EX_CMD_ADD:
406 val = (*ptr + tkey->val) & ~tkey->mask;
407 break;
408 default:
409 pr_info("tc action pedit bad command (%d)\n",
410 cmd);
411 goto bad;
412 }
413
414 *ptr = ((*ptr & tkey->mask) ^ val);
415 if (ptr == &hdata)
416 skb_store_bits(skb, hoffset + offset, ptr, 4);
417 }
418
419 goto done;
420 } else {
421 WARN(1, "pedit BUG: index %d\n", p->tcf_index);
422 }
423
424 bad:
425 p->tcf_qstats.overlimits++;
426 done:
427 bstats_update(&p->tcf_bstats, skb);
428 unlock:
429 spin_unlock(&p->tcf_lock);
430 return p->tcf_action;
431 }
432
tcf_pedit_stats_update(struct tc_action * a,u64 bytes,u64 packets,u64 drops,u64 lastuse,bool hw)433 static void tcf_pedit_stats_update(struct tc_action *a, u64 bytes, u64 packets,
434 u64 drops, u64 lastuse, bool hw)
435 {
436 struct tcf_pedit *d = to_pedit(a);
437 struct tcf_t *tm = &d->tcf_tm;
438
439 tcf_action_update_stats(a, bytes, packets, drops, hw);
440 tm->lastuse = max_t(u64, tm->lastuse, lastuse);
441 }
442
tcf_pedit_dump(struct sk_buff * skb,struct tc_action * a,int bind,int ref)443 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
444 int bind, int ref)
445 {
446 unsigned char *b = skb_tail_pointer(skb);
447 struct tcf_pedit *p = to_pedit(a);
448 struct tc_pedit *opt;
449 struct tcf_t t;
450 int s;
451
452 s = struct_size(opt, keys, p->tcfp_nkeys);
453
454 /* netlink spinlocks held above us - must use ATOMIC */
455 opt = kzalloc(s, GFP_ATOMIC);
456 if (unlikely(!opt))
457 return -ENOBUFS;
458
459 spin_lock_bh(&p->tcf_lock);
460 memcpy(opt->keys, p->tcfp_keys, flex_array_size(opt, keys, p->tcfp_nkeys));
461 opt->index = p->tcf_index;
462 opt->nkeys = p->tcfp_nkeys;
463 opt->flags = p->tcfp_flags;
464 opt->action = p->tcf_action;
465 opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
466 opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
467
468 if (p->tcfp_keys_ex) {
469 if (tcf_pedit_key_ex_dump(skb,
470 p->tcfp_keys_ex,
471 p->tcfp_nkeys))
472 goto nla_put_failure;
473
474 if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
475 goto nla_put_failure;
476 } else {
477 if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
478 goto nla_put_failure;
479 }
480
481 tcf_tm_dump(&t, &p->tcf_tm);
482 if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
483 goto nla_put_failure;
484 spin_unlock_bh(&p->tcf_lock);
485
486 kfree(opt);
487 return skb->len;
488
489 nla_put_failure:
490 spin_unlock_bh(&p->tcf_lock);
491 nlmsg_trim(skb, b);
492 kfree(opt);
493 return -1;
494 }
495
tcf_pedit_walker(struct net * net,struct sk_buff * skb,struct netlink_callback * cb,int type,const struct tc_action_ops * ops,struct netlink_ext_ack * extack)496 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
497 struct netlink_callback *cb, int type,
498 const struct tc_action_ops *ops,
499 struct netlink_ext_ack *extack)
500 {
501 struct tc_action_net *tn = net_generic(net, pedit_net_id);
502
503 return tcf_generic_walker(tn, skb, cb, type, ops, extack);
504 }
505
tcf_pedit_search(struct net * net,struct tc_action ** a,u32 index)506 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
507 {
508 struct tc_action_net *tn = net_generic(net, pedit_net_id);
509
510 return tcf_idr_search(tn, a, index);
511 }
512
513 static struct tc_action_ops act_pedit_ops = {
514 .kind = "pedit",
515 .id = TCA_ID_PEDIT,
516 .owner = THIS_MODULE,
517 .act = tcf_pedit_act,
518 .stats_update = tcf_pedit_stats_update,
519 .dump = tcf_pedit_dump,
520 .cleanup = tcf_pedit_cleanup,
521 .init = tcf_pedit_init,
522 .walk = tcf_pedit_walker,
523 .lookup = tcf_pedit_search,
524 .size = sizeof(struct tcf_pedit),
525 };
526
pedit_init_net(struct net * net)527 static __net_init int pedit_init_net(struct net *net)
528 {
529 struct tc_action_net *tn = net_generic(net, pedit_net_id);
530
531 return tc_action_net_init(net, tn, &act_pedit_ops);
532 }
533
pedit_exit_net(struct list_head * net_list)534 static void __net_exit pedit_exit_net(struct list_head *net_list)
535 {
536 tc_action_net_exit(net_list, pedit_net_id);
537 }
538
539 static struct pernet_operations pedit_net_ops = {
540 .init = pedit_init_net,
541 .exit_batch = pedit_exit_net,
542 .id = &pedit_net_id,
543 .size = sizeof(struct tc_action_net),
544 };
545
546 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
547 MODULE_DESCRIPTION("Generic Packet Editor actions");
548 MODULE_LICENSE("GPL");
549
pedit_init_module(void)550 static int __init pedit_init_module(void)
551 {
552 return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
553 }
554
pedit_cleanup_module(void)555 static void __exit pedit_cleanup_module(void)
556 {
557 tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
558 }
559
560 module_init(pedit_init_module);
561 module_exit(pedit_cleanup_module);
562