xref: /openbmc/linux/net/sched/act_pedit.c (revision 7f8256ae) 
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 #include <net/tc_wrapper.h>
24 
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_KEYS_EX]   = { .type = NLA_NESTED },
30 };
31 
32 static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
33 	[TCA_PEDIT_KEY_EX_HTYPE] =
34 		NLA_POLICY_MAX(NLA_U16, TCA_PEDIT_HDR_TYPE_MAX),
35 	[TCA_PEDIT_KEY_EX_CMD] = NLA_POLICY_MAX(NLA_U16, TCA_PEDIT_CMD_MAX),
36 };
37 
38 static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
39 							u8 n, struct netlink_ext_ack *extack)
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 			NL_SET_ERR_MSG_MOD(extack, "Can't parse more extended keys than requested");
61 			err = -EINVAL;
62 			goto err_out;
63 		}
64 		n--;
65 
66 		if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
67 			NL_SET_ERR_MSG_ATTR(extack, ka, "Unknown attribute, expected extended key");
68 			err = -EINVAL;
69 			goto err_out;
70 		}
71 
72 		err = nla_parse_nested_deprecated(tb, TCA_PEDIT_KEY_EX_MAX,
73 						  ka, pedit_key_ex_policy,
74 						  NULL);
75 		if (err)
76 			goto err_out;
77 
78 		if (NL_REQ_ATTR_CHECK(extack, nla, tb, TCA_PEDIT_KEY_EX_HTYPE)) {
79 			NL_SET_ERR_MSG(extack, "Missing required attribute");
80 			err = -EINVAL;
81 			goto err_out;
82 		}
83 
84 		if (NL_REQ_ATTR_CHECK(extack, nla, tb, TCA_PEDIT_KEY_EX_CMD)) {
85 			NL_SET_ERR_MSG(extack, "Missing required attribute");
86 			err = -EINVAL;
87 			goto err_out;
88 		}
89 
90 		k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
91 		k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
92 
93 		k++;
94 	}
95 
96 	if (n) {
97 		NL_SET_ERR_MSG_MOD(extack, "Not enough extended keys to parse");
98 		err = -EINVAL;
99 		goto err_out;
100 	}
101 
102 	return keys_ex;
103 
104 err_out:
105 	kfree(keys_ex);
106 	return ERR_PTR(err);
107 }
108 
109 static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
110 				 struct tcf_pedit_key_ex *keys_ex, int n)
111 {
112 	struct nlattr *keys_start = nla_nest_start_noflag(skb,
113 							  TCA_PEDIT_KEYS_EX);
114 
115 	if (!keys_start)
116 		goto nla_failure;
117 	for (; n > 0; n--) {
118 		struct nlattr *key_start;
119 
120 		key_start = nla_nest_start_noflag(skb, TCA_PEDIT_KEY_EX);
121 		if (!key_start)
122 			goto nla_failure;
123 
124 		if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
125 		    nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
126 			goto nla_failure;
127 
128 		nla_nest_end(skb, key_start);
129 
130 		keys_ex++;
131 	}
132 
133 	nla_nest_end(skb, keys_start);
134 
135 	return 0;
136 nla_failure:
137 	nla_nest_cancel(skb, keys_start);
138 	return -EINVAL;
139 }
140 
141 static void tcf_pedit_cleanup_rcu(struct rcu_head *head)
142 {
143 	struct tcf_pedit_parms *parms =
144 		container_of(head, struct tcf_pedit_parms, rcu);
145 
146 	kfree(parms->tcfp_keys_ex);
147 	kfree(parms->tcfp_keys);
148 
149 	kfree(parms);
150 }
151 
152 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
153 			  struct nlattr *est, struct tc_action **a,
154 			  struct tcf_proto *tp, u32 flags,
155 			  struct netlink_ext_ack *extack)
156 {
157 	struct tc_action_net *tn = net_generic(net, act_pedit_ops.net_id);
158 	bool bind = flags & TCA_ACT_FLAGS_BIND;
159 	struct tcf_chain *goto_ch = NULL;
160 	struct tcf_pedit_parms *oparms, *nparms;
161 	struct nlattr *tb[TCA_PEDIT_MAX + 1];
162 	struct tc_pedit *parm;
163 	struct nlattr *pattr;
164 	struct tcf_pedit *p;
165 	int ret = 0, err;
166 	int i, ksize;
167 	u32 index;
168 
169 	if (!nla) {
170 		NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
171 		return -EINVAL;
172 	}
173 
174 	err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
175 					  pedit_policy, NULL);
176 	if (err < 0)
177 		return err;
178 
179 	pattr = tb[TCA_PEDIT_PARMS];
180 	if (!pattr)
181 		pattr = tb[TCA_PEDIT_PARMS_EX];
182 	if (!pattr) {
183 		NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
184 		return -EINVAL;
185 	}
186 
187 	parm = nla_data(pattr);
188 
189 	index = parm->index;
190 	err = tcf_idr_check_alloc(tn, &index, a, bind);
191 	if (!err) {
192 		ret = tcf_idr_create_from_flags(tn, index, est, a,
193 						&act_pedit_ops, bind, flags);
194 		if (ret) {
195 			tcf_idr_cleanup(tn, index);
196 			return ret;
197 		}
198 		ret = ACT_P_CREATED;
199 	} else if (err > 0) {
200 		if (bind)
201 			return 0;
202 		if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
203 			ret = -EEXIST;
204 			goto out_release;
205 		}
206 	} else {
207 		return err;
208 	}
209 
210 	if (!parm->nkeys) {
211 		NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
212 		ret = -EINVAL;
213 		goto out_release;
214 	}
215 	ksize = parm->nkeys * sizeof(struct tc_pedit_key);
216 	if (nla_len(pattr) < sizeof(*parm) + ksize) {
217 		NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
218 		ret = -EINVAL;
219 		goto out_release;
220 	}
221 
222 	nparms = kzalloc(sizeof(*nparms), GFP_KERNEL);
223 	if (!nparms) {
224 		ret = -ENOMEM;
225 		goto out_release;
226 	}
227 
228 	nparms->tcfp_keys_ex =
229 		tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys, extack);
230 	if (IS_ERR(nparms->tcfp_keys_ex)) {
231 		ret = PTR_ERR(nparms->tcfp_keys_ex);
232 		goto out_free;
233 	}
234 
235 	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
236 	if (err < 0) {
237 		ret = err;
238 		goto out_free_ex;
239 	}
240 
241 	nparms->tcfp_off_max_hint = 0;
242 	nparms->tcfp_flags = parm->flags;
243 	nparms->tcfp_nkeys = parm->nkeys;
244 
245 	nparms->tcfp_keys = kmalloc(ksize, GFP_KERNEL);
246 	if (!nparms->tcfp_keys) {
247 		ret = -ENOMEM;
248 		goto put_chain;
249 	}
250 
251 	memcpy(nparms->tcfp_keys, parm->keys, ksize);
252 
253 	for (i = 0; i < nparms->tcfp_nkeys; ++i) {
254 		u32 offmask = nparms->tcfp_keys[i].offmask;
255 		u32 cur = nparms->tcfp_keys[i].off;
256 
257 		/* The AT option can be added to static offsets in the datapath */
258 		if (!offmask && cur % 4) {
259 			NL_SET_ERR_MSG_MOD(extack, "Offsets must be on 32bit boundaries");
260 			ret = -EINVAL;
261 			goto out_free_keys;
262 		}
263 
264 		/* sanitize the shift value for any later use */
265 		nparms->tcfp_keys[i].shift = min_t(size_t,
266 						   BITS_PER_TYPE(int) - 1,
267 						   nparms->tcfp_keys[i].shift);
268 
269 		/* The AT option can read a single byte, we can bound the actual
270 		 * value with uchar max.
271 		 */
272 		cur += (0xff & offmask) >> nparms->tcfp_keys[i].shift;
273 
274 		/* Each key touches 4 bytes starting from the computed offset */
275 		nparms->tcfp_off_max_hint =
276 			max(nparms->tcfp_off_max_hint, cur + 4);
277 	}
278 
279 	p = to_pedit(*a);
280 
281 	spin_lock_bh(&p->tcf_lock);
282 	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
283 	oparms = rcu_replace_pointer(p->parms, nparms, 1);
284 	spin_unlock_bh(&p->tcf_lock);
285 
286 	if (oparms)
287 		call_rcu(&oparms->rcu, tcf_pedit_cleanup_rcu);
288 
289 	if (goto_ch)
290 		tcf_chain_put_by_act(goto_ch);
291 
292 	return ret;
293 
294 out_free_keys:
295 	kfree(nparms->tcfp_keys);
296 put_chain:
297 	if (goto_ch)
298 		tcf_chain_put_by_act(goto_ch);
299 out_free_ex:
300 	kfree(nparms->tcfp_keys_ex);
301 out_free:
302 	kfree(nparms);
303 out_release:
304 	tcf_idr_release(*a, bind);
305 	return ret;
306 }
307 
308 static void tcf_pedit_cleanup(struct tc_action *a)
309 {
310 	struct tcf_pedit *p = to_pedit(a);
311 	struct tcf_pedit_parms *parms;
312 
313 	parms = rcu_dereference_protected(p->parms, 1);
314 
315 	if (parms)
316 		call_rcu(&parms->rcu, tcf_pedit_cleanup_rcu);
317 }
318 
319 static bool offset_valid(struct sk_buff *skb, int offset)
320 {
321 	if (offset > 0 && offset > skb->len)
322 		return false;
323 
324 	if  (offset < 0 && -offset > skb_headroom(skb))
325 		return false;
326 
327 	return true;
328 }
329 
330 static void pedit_skb_hdr_offset(struct sk_buff *skb,
331 				 enum pedit_header_type htype, int *hoffset)
332 {
333 	/* 'htype' is validated in the netlink parsing */
334 	switch (htype) {
335 	case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
336 		if (skb_mac_header_was_set(skb))
337 			*hoffset = skb_mac_offset(skb);
338 		break;
339 	case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
340 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
341 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
342 		*hoffset = skb_network_offset(skb);
343 		break;
344 	case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
345 	case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
346 		if (skb_transport_header_was_set(skb))
347 			*hoffset = skb_transport_offset(skb);
348 		break;
349 	default:
350 		break;
351 	}
352 }
353 
354 TC_INDIRECT_SCOPE int tcf_pedit_act(struct sk_buff *skb,
355 				    const struct tc_action *a,
356 				    struct tcf_result *res)
357 {
358 	enum pedit_header_type htype = TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
359 	enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
360 	struct tcf_pedit *p = to_pedit(a);
361 	struct tcf_pedit_key_ex *tkey_ex;
362 	struct tcf_pedit_parms *parms;
363 	struct tc_pedit_key *tkey;
364 	u32 max_offset;
365 	int i;
366 
367 	parms = rcu_dereference_bh(p->parms);
368 
369 	max_offset = (skb_transport_header_was_set(skb) ?
370 		      skb_transport_offset(skb) :
371 		      skb_network_offset(skb)) +
372 		     parms->tcfp_off_max_hint;
373 	if (skb_ensure_writable(skb, min(skb->len, max_offset)))
374 		goto done;
375 
376 	tcf_lastuse_update(&p->tcf_tm);
377 	tcf_action_update_bstats(&p->common, skb);
378 
379 	tkey = parms->tcfp_keys;
380 	tkey_ex = parms->tcfp_keys_ex;
381 
382 	for (i = parms->tcfp_nkeys; i > 0; i--, tkey++) {
383 		int offset = tkey->off;
384 		int hoffset = 0;
385 		u32 *ptr, hdata;
386 		u32 val;
387 
388 		if (tkey_ex) {
389 			htype = tkey_ex->htype;
390 			cmd = tkey_ex->cmd;
391 
392 			tkey_ex++;
393 		}
394 
395 		pedit_skb_hdr_offset(skb, htype, &hoffset);
396 
397 		if (tkey->offmask) {
398 			u8 *d, _d;
399 
400 			if (!offset_valid(skb, hoffset + tkey->at)) {
401 				pr_info_ratelimited("tc action pedit 'at' offset %d out of bounds\n",
402 						    hoffset + tkey->at);
403 				goto bad;
404 			}
405 			d = skb_header_pointer(skb, hoffset + tkey->at,
406 					       sizeof(_d), &_d);
407 			if (!d)
408 				goto bad;
409 
410 			offset += (*d & tkey->offmask) >> tkey->shift;
411 			if (offset % 4) {
412 				pr_info_ratelimited("tc action pedit offset must be on 32 bit boundaries\n");
413 				goto bad;
414 			}
415 		}
416 
417 		if (!offset_valid(skb, hoffset + offset)) {
418 			pr_info_ratelimited("tc action pedit offset %d out of bounds\n", hoffset + offset);
419 			goto bad;
420 		}
421 
422 		ptr = skb_header_pointer(skb, hoffset + offset,
423 					 sizeof(hdata), &hdata);
424 		if (!ptr)
425 			goto bad;
426 		/* just do it, baby */
427 		switch (cmd) {
428 		case TCA_PEDIT_KEY_EX_CMD_SET:
429 			val = tkey->val;
430 			break;
431 		case TCA_PEDIT_KEY_EX_CMD_ADD:
432 			val = (*ptr + tkey->val) & ~tkey->mask;
433 			break;
434 		default:
435 			pr_info_ratelimited("tc action pedit bad command (%d)\n", cmd);
436 			goto bad;
437 		}
438 
439 		*ptr = ((*ptr & tkey->mask) ^ val);
440 		if (ptr == &hdata)
441 			skb_store_bits(skb, hoffset + offset, ptr, 4);
442 	}
443 
444 	goto done;
445 
446 bad:
447 	tcf_action_inc_overlimit_qstats(&p->common);
448 done:
449 	return p->tcf_action;
450 }
451 
452 static void tcf_pedit_stats_update(struct tc_action *a, u64 bytes, u64 packets,
453 				   u64 drops, u64 lastuse, bool hw)
454 {
455 	struct tcf_pedit *d = to_pedit(a);
456 	struct tcf_t *tm = &d->tcf_tm;
457 
458 	tcf_action_update_stats(a, bytes, packets, drops, hw);
459 	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
460 }
461 
462 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
463 			  int bind, int ref)
464 {
465 	unsigned char *b = skb_tail_pointer(skb);
466 	struct tcf_pedit *p = to_pedit(a);
467 	struct tcf_pedit_parms *parms;
468 	struct tc_pedit *opt;
469 	struct tcf_t t;
470 	int s;
471 
472 	spin_lock_bh(&p->tcf_lock);
473 	parms = rcu_dereference_protected(p->parms, 1);
474 	s = struct_size(opt, keys, parms->tcfp_nkeys);
475 
476 	opt = kzalloc(s, GFP_ATOMIC);
477 	if (unlikely(!opt)) {
478 		spin_unlock_bh(&p->tcf_lock);
479 		return -ENOBUFS;
480 	}
481 
482 	memcpy(opt->keys, parms->tcfp_keys,
483 	       flex_array_size(opt, keys, parms->tcfp_nkeys));
484 	opt->index = p->tcf_index;
485 	opt->nkeys = parms->tcfp_nkeys;
486 	opt->flags = parms->tcfp_flags;
487 	opt->action = p->tcf_action;
488 	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
489 	opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
490 
491 	if (parms->tcfp_keys_ex) {
492 		if (tcf_pedit_key_ex_dump(skb, parms->tcfp_keys_ex,
493 					  parms->tcfp_nkeys))
494 			goto nla_put_failure;
495 
496 		if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
497 			goto nla_put_failure;
498 	} else {
499 		if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
500 			goto nla_put_failure;
501 	}
502 
503 	tcf_tm_dump(&t, &p->tcf_tm);
504 	if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
505 		goto nla_put_failure;
506 	spin_unlock_bh(&p->tcf_lock);
507 
508 	kfree(opt);
509 	return skb->len;
510 
511 nla_put_failure:
512 	spin_unlock_bh(&p->tcf_lock);
513 	nlmsg_trim(skb, b);
514 	kfree(opt);
515 	return -1;
516 }
517 
518 static int tcf_pedit_offload_act_setup(struct tc_action *act, void *entry_data,
519 				       u32 *index_inc, bool bind,
520 				       struct netlink_ext_ack *extack)
521 {
522 	if (bind) {
523 		struct flow_action_entry *entry = entry_data;
524 		int k;
525 
526 		for (k = 0; k < tcf_pedit_nkeys(act); k++) {
527 			switch (tcf_pedit_cmd(act, k)) {
528 			case TCA_PEDIT_KEY_EX_CMD_SET:
529 				entry->id = FLOW_ACTION_MANGLE;
530 				break;
531 			case TCA_PEDIT_KEY_EX_CMD_ADD:
532 				entry->id = FLOW_ACTION_ADD;
533 				break;
534 			default:
535 				NL_SET_ERR_MSG_MOD(extack, "Unsupported pedit command offload");
536 				return -EOPNOTSUPP;
537 			}
538 			entry->mangle.htype = tcf_pedit_htype(act, k);
539 			entry->mangle.mask = tcf_pedit_mask(act, k);
540 			entry->mangle.val = tcf_pedit_val(act, k);
541 			entry->mangle.offset = tcf_pedit_offset(act, k);
542 			entry->hw_stats = tc_act_hw_stats(act->hw_stats);
543 			entry++;
544 		}
545 		*index_inc = k;
546 	} else {
547 		struct flow_offload_action *fl_action = entry_data;
548 		u32 cmd = tcf_pedit_cmd(act, 0);
549 		int k;
550 
551 		switch (cmd) {
552 		case TCA_PEDIT_KEY_EX_CMD_SET:
553 			fl_action->id = FLOW_ACTION_MANGLE;
554 			break;
555 		case TCA_PEDIT_KEY_EX_CMD_ADD:
556 			fl_action->id = FLOW_ACTION_ADD;
557 			break;
558 		default:
559 			NL_SET_ERR_MSG_MOD(extack, "Unsupported pedit command offload");
560 			return -EOPNOTSUPP;
561 		}
562 
563 		for (k = 1; k < tcf_pedit_nkeys(act); k++) {
564 			if (cmd != tcf_pedit_cmd(act, k)) {
565 				NL_SET_ERR_MSG_MOD(extack, "Unsupported pedit command offload");
566 				return -EOPNOTSUPP;
567 			}
568 		}
569 	}
570 
571 	return 0;
572 }
573 
574 static struct tc_action_ops act_pedit_ops = {
575 	.kind		=	"pedit",
576 	.id		=	TCA_ID_PEDIT,
577 	.owner		=	THIS_MODULE,
578 	.act		=	tcf_pedit_act,
579 	.stats_update	=	tcf_pedit_stats_update,
580 	.dump		=	tcf_pedit_dump,
581 	.cleanup	=	tcf_pedit_cleanup,
582 	.init		=	tcf_pedit_init,
583 	.offload_act_setup =	tcf_pedit_offload_act_setup,
584 	.size		=	sizeof(struct tcf_pedit),
585 };
586 
587 static __net_init int pedit_init_net(struct net *net)
588 {
589 	struct tc_action_net *tn = net_generic(net, act_pedit_ops.net_id);
590 
591 	return tc_action_net_init(net, tn, &act_pedit_ops);
592 }
593 
594 static void __net_exit pedit_exit_net(struct list_head *net_list)
595 {
596 	tc_action_net_exit(net_list, act_pedit_ops.net_id);
597 }
598 
599 static struct pernet_operations pedit_net_ops = {
600 	.init = pedit_init_net,
601 	.exit_batch = pedit_exit_net,
602 	.id   = &act_pedit_ops.net_id,
603 	.size = sizeof(struct tc_action_net),
604 };
605 
606 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
607 MODULE_DESCRIPTION("Generic Packet Editor actions");
608 MODULE_LICENSE("GPL");
609 
610 static int __init pedit_init_module(void)
611 {
612 	return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
613 }
614 
615 static void __exit pedit_cleanup_module(void)
616 {
617 	tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
618 }
619 
620 module_init(pedit_init_module);
621 module_exit(pedit_cleanup_module);
622