xref: /openbmc/linux/net/sched/act_pedit.c (revision 15b209cd) 
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 struct tc_action_ops act_pedit_ops;
25 
26 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
27 	[TCA_PEDIT_PARMS]	= { .len = sizeof(struct tc_pedit) },
28 	[TCA_PEDIT_KEYS_EX]   = { .type = NLA_NESTED },
29 };
30 
31 static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
32 	[TCA_PEDIT_KEY_EX_HTYPE]  = { .type = NLA_U16 },
33 	[TCA_PEDIT_KEY_EX_CMD]	  = { .type = NLA_U16 },
34 };
35 
36 static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
37 							u8 n)
38 {
39 	struct tcf_pedit_key_ex *keys_ex;
40 	struct tcf_pedit_key_ex *k;
41 	const struct nlattr *ka;
42 	int err = -EINVAL;
43 	int rem;
44 
45 	if (!nla)
46 		return NULL;
47 
48 	keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
49 	if (!keys_ex)
50 		return ERR_PTR(-ENOMEM);
51 
52 	k = keys_ex;
53 
54 	nla_for_each_nested(ka, nla, rem) {
55 		struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
56 
57 		if (!n) {
58 			err = -EINVAL;
59 			goto err_out;
60 		}
61 		n--;
62 
63 		if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
64 			err = -EINVAL;
65 			goto err_out;
66 		}
67 
68 		err = nla_parse_nested_deprecated(tb, TCA_PEDIT_KEY_EX_MAX,
69 						  ka, pedit_key_ex_policy,
70 						  NULL);
71 		if (err)
72 			goto err_out;
73 
74 		if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
75 		    !tb[TCA_PEDIT_KEY_EX_CMD]) {
76 			err = -EINVAL;
77 			goto err_out;
78 		}
79 
80 		k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
81 		k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
82 
83 		if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
84 		    k->cmd > TCA_PEDIT_CMD_MAX) {
85 			err = -EINVAL;
86 			goto err_out;
87 		}
88 
89 		k++;
90 	}
91 
92 	if (n) {
93 		err = -EINVAL;
94 		goto err_out;
95 	}
96 
97 	return keys_ex;
98 
99 err_out:
100 	kfree(keys_ex);
101 	return ERR_PTR(err);
102 }
103 
104 static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
105 				 struct tcf_pedit_key_ex *keys_ex, int n)
106 {
107 	struct nlattr *keys_start = nla_nest_start_noflag(skb,
108 							  TCA_PEDIT_KEYS_EX);
109 
110 	if (!keys_start)
111 		goto nla_failure;
112 	for (; n > 0; n--) {
113 		struct nlattr *key_start;
114 
115 		key_start = nla_nest_start_noflag(skb, TCA_PEDIT_KEY_EX);
116 		if (!key_start)
117 			goto nla_failure;
118 
119 		if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
120 		    nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
121 			goto nla_failure;
122 
123 		nla_nest_end(skb, key_start);
124 
125 		keys_ex++;
126 	}
127 
128 	nla_nest_end(skb, keys_start);
129 
130 	return 0;
131 nla_failure:
132 	nla_nest_cancel(skb, keys_start);
133 	return -EINVAL;
134 }
135 
136 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
137 			  struct nlattr *est, struct tc_action **a,
138 			  struct tcf_proto *tp, u32 flags,
139 			  struct netlink_ext_ack *extack)
140 {
141 	struct tc_action_net *tn = net_generic(net, act_pedit_ops.net_id);
142 	bool bind = flags & TCA_ACT_FLAGS_BIND;
143 	struct nlattr *tb[TCA_PEDIT_MAX + 1];
144 	struct tcf_chain *goto_ch = NULL;
145 	struct tc_pedit_key *keys = NULL;
146 	struct tcf_pedit_key_ex *keys_ex;
147 	struct tc_pedit *parm;
148 	struct nlattr *pattr;
149 	struct tcf_pedit *p;
150 	int ret = 0, err;
151 	int i, ksize;
152 	u32 index;
153 
154 	if (!nla) {
155 		NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
156 		return -EINVAL;
157 	}
158 
159 	err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
160 					  pedit_policy, NULL);
161 	if (err < 0)
162 		return err;
163 
164 	pattr = tb[TCA_PEDIT_PARMS];
165 	if (!pattr)
166 		pattr = tb[TCA_PEDIT_PARMS_EX];
167 	if (!pattr) {
168 		NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
169 		return -EINVAL;
170 	}
171 
172 	parm = nla_data(pattr);
173 	if (!parm->nkeys) {
174 		NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
175 		return -EINVAL;
176 	}
177 	ksize = parm->nkeys * sizeof(struct tc_pedit_key);
178 	if (nla_len(pattr) < sizeof(*parm) + ksize) {
179 		NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
180 		return -EINVAL;
181 	}
182 
183 	keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
184 	if (IS_ERR(keys_ex))
185 		return PTR_ERR(keys_ex);
186 
187 	index = parm->index;
188 	err = tcf_idr_check_alloc(tn, &index, a, bind);
189 	if (!err) {
190 		ret = tcf_idr_create(tn, index, est, a,
191 				     &act_pedit_ops, bind, false, flags);
192 		if (ret) {
193 			tcf_idr_cleanup(tn, index);
194 			goto out_free;
195 		}
196 		ret = ACT_P_CREATED;
197 	} else if (err > 0) {
198 		if (bind)
199 			goto out_free;
200 		if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
201 			ret = -EEXIST;
202 			goto out_release;
203 		}
204 	} else {
205 		ret = err;
206 		goto out_free;
207 	}
208 
209 	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
210 	if (err < 0) {
211 		ret = err;
212 		goto out_release;
213 	}
214 	p = to_pedit(*a);
215 	spin_lock_bh(&p->tcf_lock);
216 
217 	if (ret == ACT_P_CREATED ||
218 	    (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
219 		keys = kmalloc(ksize, GFP_ATOMIC);
220 		if (!keys) {
221 			spin_unlock_bh(&p->tcf_lock);
222 			ret = -ENOMEM;
223 			goto put_chain;
224 		}
225 		kfree(p->tcfp_keys);
226 		p->tcfp_keys = keys;
227 		p->tcfp_nkeys = parm->nkeys;
228 	}
229 	memcpy(p->tcfp_keys, parm->keys, ksize);
230 	p->tcfp_off_max_hint = 0;
231 	for (i = 0; i < p->tcfp_nkeys; ++i) {
232 		u32 cur = p->tcfp_keys[i].off;
233 
234 		/* sanitize the shift value for any later use */
235 		p->tcfp_keys[i].shift = min_t(size_t, BITS_PER_TYPE(int) - 1,
236 					      p->tcfp_keys[i].shift);
237 
238 		/* The AT option can read a single byte, we can bound the actual
239 		 * value with uchar max.
240 		 */
241 		cur += (0xff & p->tcfp_keys[i].offmask) >> p->tcfp_keys[i].shift;
242 
243 		/* Each key touches 4 bytes starting from the computed offset */
244 		p->tcfp_off_max_hint = max(p->tcfp_off_max_hint, cur + 4);
245 	}
246 
247 	p->tcfp_flags = parm->flags;
248 	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
249 
250 	kfree(p->tcfp_keys_ex);
251 	p->tcfp_keys_ex = keys_ex;
252 
253 	spin_unlock_bh(&p->tcf_lock);
254 	if (goto_ch)
255 		tcf_chain_put_by_act(goto_ch);
256 	return ret;
257 
258 put_chain:
259 	if (goto_ch)
260 		tcf_chain_put_by_act(goto_ch);
261 out_release:
262 	tcf_idr_release(*a, bind);
263 out_free:
264 	kfree(keys_ex);
265 	return ret;
266 
267 }
268 
269 static void tcf_pedit_cleanup(struct tc_action *a)
270 {
271 	struct tcf_pedit *p = to_pedit(a);
272 	struct tc_pedit_key *keys = p->tcfp_keys;
273 
274 	kfree(keys);
275 	kfree(p->tcfp_keys_ex);
276 }
277 
278 static bool offset_valid(struct sk_buff *skb, int offset)
279 {
280 	if (offset > 0 && offset > skb->len)
281 		return false;
282 
283 	if  (offset < 0 && -offset > skb_headroom(skb))
284 		return false;
285 
286 	return true;
287 }
288 
289 static int pedit_skb_hdr_offset(struct sk_buff *skb,
290 				enum pedit_header_type htype, int *hoffset)
291 {
292 	int ret = -EINVAL;
293 
294 	switch (htype) {
295 	case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
296 		if (skb_mac_header_was_set(skb)) {
297 			*hoffset = skb_mac_offset(skb);
298 			ret = 0;
299 		}
300 		break;
301 	case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
302 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
303 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
304 		*hoffset = skb_network_offset(skb);
305 		ret = 0;
306 		break;
307 	case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
308 	case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
309 		if (skb_transport_header_was_set(skb)) {
310 			*hoffset = skb_transport_offset(skb);
311 			ret = 0;
312 		}
313 		break;
314 	default:
315 		ret = -EINVAL;
316 		break;
317 	}
318 
319 	return ret;
320 }
321 
322 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
323 			 struct tcf_result *res)
324 {
325 	struct tcf_pedit *p = to_pedit(a);
326 	u32 max_offset;
327 	int i;
328 
329 	spin_lock(&p->tcf_lock);
330 
331 	max_offset = (skb_transport_header_was_set(skb) ?
332 		      skb_transport_offset(skb) :
333 		      skb_network_offset(skb)) +
334 		     p->tcfp_off_max_hint;
335 	if (skb_ensure_writable(skb, min(skb->len, max_offset)))
336 		goto unlock;
337 
338 	tcf_lastuse_update(&p->tcf_tm);
339 
340 	if (p->tcfp_nkeys > 0) {
341 		struct tc_pedit_key *tkey = p->tcfp_keys;
342 		struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
343 		enum pedit_header_type htype =
344 			TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
345 		enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
346 
347 		for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
348 			u32 *ptr, hdata;
349 			int offset = tkey->off;
350 			int hoffset;
351 			u32 val;
352 			int rc;
353 
354 			if (tkey_ex) {
355 				htype = tkey_ex->htype;
356 				cmd = tkey_ex->cmd;
357 
358 				tkey_ex++;
359 			}
360 
361 			rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
362 			if (rc) {
363 				pr_info("tc action pedit bad header type specified (0x%x)\n",
364 					htype);
365 				goto bad;
366 			}
367 
368 			if (tkey->offmask) {
369 				u8 *d, _d;
370 
371 				if (!offset_valid(skb, hoffset + tkey->at)) {
372 					pr_info("tc action pedit 'at' offset %d out of bounds\n",
373 						hoffset + tkey->at);
374 					goto bad;
375 				}
376 				d = skb_header_pointer(skb, hoffset + tkey->at,
377 						       sizeof(_d), &_d);
378 				if (!d)
379 					goto bad;
380 				offset += (*d & tkey->offmask) >> tkey->shift;
381 			}
382 
383 			if (offset % 4) {
384 				pr_info("tc action pedit offset must be on 32 bit boundaries\n");
385 				goto bad;
386 			}
387 
388 			if (!offset_valid(skb, hoffset + offset)) {
389 				pr_info("tc action pedit offset %d out of bounds\n",
390 					hoffset + offset);
391 				goto bad;
392 			}
393 
394 			ptr = skb_header_pointer(skb, hoffset + offset,
395 						 sizeof(hdata), &hdata);
396 			if (!ptr)
397 				goto bad;
398 			/* just do it, baby */
399 			switch (cmd) {
400 			case TCA_PEDIT_KEY_EX_CMD_SET:
401 				val = tkey->val;
402 				break;
403 			case TCA_PEDIT_KEY_EX_CMD_ADD:
404 				val = (*ptr + tkey->val) & ~tkey->mask;
405 				break;
406 			default:
407 				pr_info("tc action pedit bad command (%d)\n",
408 					cmd);
409 				goto bad;
410 			}
411 
412 			*ptr = ((*ptr & tkey->mask) ^ val);
413 			if (ptr == &hdata)
414 				skb_store_bits(skb, hoffset + offset, ptr, 4);
415 		}
416 
417 		goto done;
418 	} else {
419 		WARN(1, "pedit BUG: index %d\n", p->tcf_index);
420 	}
421 
422 bad:
423 	p->tcf_qstats.overlimits++;
424 done:
425 	bstats_update(&p->tcf_bstats, skb);
426 unlock:
427 	spin_unlock(&p->tcf_lock);
428 	return p->tcf_action;
429 }
430 
431 static void tcf_pedit_stats_update(struct tc_action *a, u64 bytes, u64 packets,
432 				   u64 drops, u64 lastuse, bool hw)
433 {
434 	struct tcf_pedit *d = to_pedit(a);
435 	struct tcf_t *tm = &d->tcf_tm;
436 
437 	tcf_action_update_stats(a, bytes, packets, drops, hw);
438 	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
439 }
440 
441 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
442 			  int bind, int ref)
443 {
444 	unsigned char *b = skb_tail_pointer(skb);
445 	struct tcf_pedit *p = to_pedit(a);
446 	struct tc_pedit *opt;
447 	struct tcf_t t;
448 	int s;
449 
450 	s = struct_size(opt, keys, p->tcfp_nkeys);
451 
452 	/* netlink spinlocks held above us - must use ATOMIC */
453 	opt = kzalloc(s, GFP_ATOMIC);
454 	if (unlikely(!opt))
455 		return -ENOBUFS;
456 
457 	spin_lock_bh(&p->tcf_lock);
458 	memcpy(opt->keys, p->tcfp_keys, flex_array_size(opt, keys, p->tcfp_nkeys));
459 	opt->index = p->tcf_index;
460 	opt->nkeys = p->tcfp_nkeys;
461 	opt->flags = p->tcfp_flags;
462 	opt->action = p->tcf_action;
463 	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
464 	opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
465 
466 	if (p->tcfp_keys_ex) {
467 		if (tcf_pedit_key_ex_dump(skb,
468 					  p->tcfp_keys_ex,
469 					  p->tcfp_nkeys))
470 			goto nla_put_failure;
471 
472 		if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
473 			goto nla_put_failure;
474 	} else {
475 		if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
476 			goto nla_put_failure;
477 	}
478 
479 	tcf_tm_dump(&t, &p->tcf_tm);
480 	if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
481 		goto nla_put_failure;
482 	spin_unlock_bh(&p->tcf_lock);
483 
484 	kfree(opt);
485 	return skb->len;
486 
487 nla_put_failure:
488 	spin_unlock_bh(&p->tcf_lock);
489 	nlmsg_trim(skb, b);
490 	kfree(opt);
491 	return -1;
492 }
493 
494 static int tcf_pedit_offload_act_setup(struct tc_action *act, void *entry_data,
495 				       u32 *index_inc, bool bind,
496 				       struct netlink_ext_ack *extack)
497 {
498 	if (bind) {
499 		struct flow_action_entry *entry = entry_data;
500 		int k;
501 
502 		for (k = 0; k < tcf_pedit_nkeys(act); k++) {
503 			switch (tcf_pedit_cmd(act, k)) {
504 			case TCA_PEDIT_KEY_EX_CMD_SET:
505 				entry->id = FLOW_ACTION_MANGLE;
506 				break;
507 			case TCA_PEDIT_KEY_EX_CMD_ADD:
508 				entry->id = FLOW_ACTION_ADD;
509 				break;
510 			default:
511 				NL_SET_ERR_MSG_MOD(extack, "Unsupported pedit command offload");
512 				return -EOPNOTSUPP;
513 			}
514 			entry->mangle.htype = tcf_pedit_htype(act, k);
515 			entry->mangle.mask = tcf_pedit_mask(act, k);
516 			entry->mangle.val = tcf_pedit_val(act, k);
517 			entry->mangle.offset = tcf_pedit_offset(act, k);
518 			entry->hw_stats = tc_act_hw_stats(act->hw_stats);
519 			entry++;
520 		}
521 		*index_inc = k;
522 	} else {
523 		return -EOPNOTSUPP;
524 	}
525 
526 	return 0;
527 }
528 
529 static struct tc_action_ops act_pedit_ops = {
530 	.kind		=	"pedit",
531 	.id		=	TCA_ID_PEDIT,
532 	.owner		=	THIS_MODULE,
533 	.act		=	tcf_pedit_act,
534 	.stats_update	=	tcf_pedit_stats_update,
535 	.dump		=	tcf_pedit_dump,
536 	.cleanup	=	tcf_pedit_cleanup,
537 	.init		=	tcf_pedit_init,
538 	.offload_act_setup =	tcf_pedit_offload_act_setup,
539 	.size		=	sizeof(struct tcf_pedit),
540 };
541 
542 static __net_init int pedit_init_net(struct net *net)
543 {
544 	struct tc_action_net *tn = net_generic(net, act_pedit_ops.net_id);
545 
546 	return tc_action_net_init(net, tn, &act_pedit_ops);
547 }
548 
549 static void __net_exit pedit_exit_net(struct list_head *net_list)
550 {
551 	tc_action_net_exit(net_list, act_pedit_ops.net_id);
552 }
553 
554 static struct pernet_operations pedit_net_ops = {
555 	.init = pedit_init_net,
556 	.exit_batch = pedit_exit_net,
557 	.id   = &act_pedit_ops.net_id,
558 	.size = sizeof(struct tc_action_net),
559 };
560 
561 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
562 MODULE_DESCRIPTION("Generic Packet Editor actions");
563 MODULE_LICENSE("GPL");
564 
565 static int __init pedit_init_module(void)
566 {
567 	return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
568 }
569 
570 static void __exit pedit_cleanup_module(void)
571 {
572 	tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
573 }
574 
575 module_init(pedit_init_module);
576 module_exit(pedit_cleanup_module);
577