xref: /linux/net/sched/act_pedit.c (revision a1c3be890440a1769ed6f822376a3e3ab0d42994) 
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_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]  = { .type = NLA_U16 },
34 	[TCA_PEDIT_KEY_EX_CMD]	  = { .type = NLA_U16 },
35 };
36 
37 static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
38 							u8 n)
39 {
40 	struct tcf_pedit_key_ex *keys_ex;
41 	struct tcf_pedit_key_ex *k;
42 	const struct nlattr *ka;
43 	int err = -EINVAL;
44 	int rem;
45 
46 	if (!nla)
47 		return NULL;
48 
49 	keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
50 	if (!keys_ex)
51 		return ERR_PTR(-ENOMEM);
52 
53 	k = keys_ex;
54 
55 	nla_for_each_nested(ka, nla, rem) {
56 		struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
57 
58 		if (!n) {
59 			err = -EINVAL;
60 			goto err_out;
61 		}
62 		n--;
63 
64 		if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
65 			err = -EINVAL;
66 			goto err_out;
67 		}
68 
69 		err = nla_parse_nested_deprecated(tb, TCA_PEDIT_KEY_EX_MAX,
70 						  ka, pedit_key_ex_policy,
71 						  NULL);
72 		if (err)
73 			goto err_out;
74 
75 		if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
76 		    !tb[TCA_PEDIT_KEY_EX_CMD]) {
77 			err = -EINVAL;
78 			goto err_out;
79 		}
80 
81 		k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
82 		k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
83 
84 		if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
85 		    k->cmd > TCA_PEDIT_CMD_MAX) {
86 			err = -EINVAL;
87 			goto err_out;
88 		}
89 
90 		k++;
91 	}
92 
93 	if (n) {
94 		err = -EINVAL;
95 		goto err_out;
96 	}
97 
98 	return keys_ex;
99 
100 err_out:
101 	kfree(keys_ex);
102 	return ERR_PTR(err);
103 }
104 
105 static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
106 				 struct tcf_pedit_key_ex *keys_ex, int n)
107 {
108 	struct nlattr *keys_start = nla_nest_start_noflag(skb,
109 							  TCA_PEDIT_KEYS_EX);
110 
111 	if (!keys_start)
112 		goto nla_failure;
113 	for (; n > 0; n--) {
114 		struct nlattr *key_start;
115 
116 		key_start = nla_nest_start_noflag(skb, TCA_PEDIT_KEY_EX);
117 		if (!key_start)
118 			goto nla_failure;
119 
120 		if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
121 		    nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
122 			goto nla_failure;
123 
124 		nla_nest_end(skb, key_start);
125 
126 		keys_ex++;
127 	}
128 
129 	nla_nest_end(skb, keys_start);
130 
131 	return 0;
132 nla_failure:
133 	nla_nest_cancel(skb, keys_start);
134 	return -EINVAL;
135 }
136 
137 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
138 			  struct nlattr *est, struct tc_action **a,
139 			  int ovr, int bind, bool rtnl_held,
140 			  struct tcf_proto *tp, u32 flags,
141 			  struct netlink_ext_ack *extack)
142 {
143 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
144 	struct nlattr *tb[TCA_PEDIT_MAX + 1];
145 	struct tcf_chain *goto_ch = NULL;
146 	struct tc_pedit_key *keys = NULL;
147 	struct tcf_pedit_key_ex *keys_ex;
148 	struct tc_pedit *parm;
149 	struct nlattr *pattr;
150 	struct tcf_pedit *p;
151 	int ret = 0, err;
152 	int ksize;
153 	u32 index;
154 
155 	if (!nla) {
156 		NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
157 		return -EINVAL;
158 	}
159 
160 	err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
161 					  pedit_policy, NULL);
162 	if (err < 0)
163 		return err;
164 
165 	pattr = tb[TCA_PEDIT_PARMS];
166 	if (!pattr)
167 		pattr = tb[TCA_PEDIT_PARMS_EX];
168 	if (!pattr) {
169 		NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
170 		return -EINVAL;
171 	}
172 
173 	parm = nla_data(pattr);
174 	if (!parm->nkeys) {
175 		NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
176 		return -EINVAL;
177 	}
178 	ksize = parm->nkeys * sizeof(struct tc_pedit_key);
179 	if (nla_len(pattr) < sizeof(*parm) + ksize) {
180 		NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
181 		return -EINVAL;
182 	}
183 
184 	keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
185 	if (IS_ERR(keys_ex))
186 		return PTR_ERR(keys_ex);
187 
188 	index = parm->index;
189 	err = tcf_idr_check_alloc(tn, &index, a, bind);
190 	if (!err) {
191 		ret = tcf_idr_create(tn, index, est, a,
192 				     &act_pedit_ops, bind, false, 0);
193 		if (ret) {
194 			tcf_idr_cleanup(tn, index);
195 			goto out_free;
196 		}
197 		ret = ACT_P_CREATED;
198 	} else if (err > 0) {
199 		if (bind)
200 			goto out_free;
201 		if (!ovr) {
202 			ret = -EEXIST;
203 			goto out_release;
204 		}
205 	} else {
206 		ret = err;
207 		goto out_free;
208 	}
209 
210 	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
211 	if (err < 0) {
212 		ret = err;
213 		goto out_release;
214 	}
215 	p = to_pedit(*a);
216 	spin_lock_bh(&p->tcf_lock);
217 
218 	if (ret == ACT_P_CREATED ||
219 	    (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
220 		keys = kmalloc(ksize, GFP_ATOMIC);
221 		if (!keys) {
222 			spin_unlock_bh(&p->tcf_lock);
223 			ret = -ENOMEM;
224 			goto put_chain;
225 		}
226 		kfree(p->tcfp_keys);
227 		p->tcfp_keys = keys;
228 		p->tcfp_nkeys = parm->nkeys;
229 	}
230 	memcpy(p->tcfp_keys, parm->keys, ksize);
231 
232 	p->tcfp_flags = parm->flags;
233 	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
234 
235 	kfree(p->tcfp_keys_ex);
236 	p->tcfp_keys_ex = keys_ex;
237 
238 	spin_unlock_bh(&p->tcf_lock);
239 	if (goto_ch)
240 		tcf_chain_put_by_act(goto_ch);
241 	return ret;
242 
243 put_chain:
244 	if (goto_ch)
245 		tcf_chain_put_by_act(goto_ch);
246 out_release:
247 	tcf_idr_release(*a, bind);
248 out_free:
249 	kfree(keys_ex);
250 	return ret;
251 
252 }
253 
254 static void tcf_pedit_cleanup(struct tc_action *a)
255 {
256 	struct tcf_pedit *p = to_pedit(a);
257 	struct tc_pedit_key *keys = p->tcfp_keys;
258 
259 	kfree(keys);
260 	kfree(p->tcfp_keys_ex);
261 }
262 
263 static bool offset_valid(struct sk_buff *skb, int offset)
264 {
265 	if (offset > 0 && offset > skb->len)
266 		return false;
267 
268 	if  (offset < 0 && -offset > skb_headroom(skb))
269 		return false;
270 
271 	return true;
272 }
273 
274 static int pedit_skb_hdr_offset(struct sk_buff *skb,
275 				enum pedit_header_type htype, int *hoffset)
276 {
277 	int ret = -EINVAL;
278 
279 	switch (htype) {
280 	case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
281 		if (skb_mac_header_was_set(skb)) {
282 			*hoffset = skb_mac_offset(skb);
283 			ret = 0;
284 		}
285 		break;
286 	case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
287 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
288 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
289 		*hoffset = skb_network_offset(skb);
290 		ret = 0;
291 		break;
292 	case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
293 	case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
294 		if (skb_transport_header_was_set(skb)) {
295 			*hoffset = skb_transport_offset(skb);
296 			ret = 0;
297 		}
298 		break;
299 	default:
300 		ret = -EINVAL;
301 		break;
302 	}
303 
304 	return ret;
305 }
306 
307 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
308 			 struct tcf_result *res)
309 {
310 	struct tcf_pedit *p = to_pedit(a);
311 	int i;
312 
313 	if (skb_unclone(skb, GFP_ATOMIC))
314 		return p->tcf_action;
315 
316 	spin_lock(&p->tcf_lock);
317 
318 	tcf_lastuse_update(&p->tcf_tm);
319 
320 	if (p->tcfp_nkeys > 0) {
321 		struct tc_pedit_key *tkey = p->tcfp_keys;
322 		struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
323 		enum pedit_header_type htype =
324 			TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
325 		enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
326 
327 		for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
328 			u32 *ptr, hdata;
329 			int offset = tkey->off;
330 			int hoffset;
331 			u32 val;
332 			int rc;
333 
334 			if (tkey_ex) {
335 				htype = tkey_ex->htype;
336 				cmd = tkey_ex->cmd;
337 
338 				tkey_ex++;
339 			}
340 
341 			rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
342 			if (rc) {
343 				pr_info("tc action pedit bad header type specified (0x%x)\n",
344 					htype);
345 				goto bad;
346 			}
347 
348 			if (tkey->offmask) {
349 				u8 *d, _d;
350 
351 				if (!offset_valid(skb, hoffset + tkey->at)) {
352 					pr_info("tc action pedit 'at' offset %d out of bounds\n",
353 						hoffset + tkey->at);
354 					goto bad;
355 				}
356 				d = skb_header_pointer(skb, hoffset + tkey->at,
357 						       sizeof(_d), &_d);
358 				if (!d)
359 					goto bad;
360 				offset += (*d & tkey->offmask) >> tkey->shift;
361 			}
362 
363 			if (offset % 4) {
364 				pr_info("tc action pedit offset must be on 32 bit boundaries\n");
365 				goto bad;
366 			}
367 
368 			if (!offset_valid(skb, hoffset + offset)) {
369 				pr_info("tc action pedit offset %d out of bounds\n",
370 					hoffset + offset);
371 				goto bad;
372 			}
373 
374 			ptr = skb_header_pointer(skb, hoffset + offset,
375 						 sizeof(hdata), &hdata);
376 			if (!ptr)
377 				goto bad;
378 			/* just do it, baby */
379 			switch (cmd) {
380 			case TCA_PEDIT_KEY_EX_CMD_SET:
381 				val = tkey->val;
382 				break;
383 			case TCA_PEDIT_KEY_EX_CMD_ADD:
384 				val = (*ptr + tkey->val) & ~tkey->mask;
385 				break;
386 			default:
387 				pr_info("tc action pedit bad command (%d)\n",
388 					cmd);
389 				goto bad;
390 			}
391 
392 			*ptr = ((*ptr & tkey->mask) ^ val);
393 			if (ptr == &hdata)
394 				skb_store_bits(skb, hoffset + offset, ptr, 4);
395 		}
396 
397 		goto done;
398 	} else {
399 		WARN(1, "pedit BUG: index %d\n", p->tcf_index);
400 	}
401 
402 bad:
403 	p->tcf_qstats.overlimits++;
404 done:
405 	bstats_update(&p->tcf_bstats, skb);
406 	spin_unlock(&p->tcf_lock);
407 	return p->tcf_action;
408 }
409 
410 static void tcf_pedit_stats_update(struct tc_action *a, u64 bytes, u64 packets,
411 				   u64 drops, u64 lastuse, bool hw)
412 {
413 	struct tcf_pedit *d = to_pedit(a);
414 	struct tcf_t *tm = &d->tcf_tm;
415 
416 	tcf_action_update_stats(a, bytes, packets, drops, hw);
417 	tm->lastuse = max_t(u64, tm->lastuse, lastuse);
418 }
419 
420 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
421 			  int bind, int ref)
422 {
423 	unsigned char *b = skb_tail_pointer(skb);
424 	struct tcf_pedit *p = to_pedit(a);
425 	struct tc_pedit *opt;
426 	struct tcf_t t;
427 	int s;
428 
429 	s = struct_size(opt, keys, p->tcfp_nkeys);
430 
431 	/* netlink spinlocks held above us - must use ATOMIC */
432 	opt = kzalloc(s, GFP_ATOMIC);
433 	if (unlikely(!opt))
434 		return -ENOBUFS;
435 
436 	spin_lock_bh(&p->tcf_lock);
437 	memcpy(opt->keys, p->tcfp_keys, flex_array_size(opt, keys, p->tcfp_nkeys));
438 	opt->index = p->tcf_index;
439 	opt->nkeys = p->tcfp_nkeys;
440 	opt->flags = p->tcfp_flags;
441 	opt->action = p->tcf_action;
442 	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
443 	opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
444 
445 	if (p->tcfp_keys_ex) {
446 		if (tcf_pedit_key_ex_dump(skb,
447 					  p->tcfp_keys_ex,
448 					  p->tcfp_nkeys))
449 			goto nla_put_failure;
450 
451 		if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
452 			goto nla_put_failure;
453 	} else {
454 		if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
455 			goto nla_put_failure;
456 	}
457 
458 	tcf_tm_dump(&t, &p->tcf_tm);
459 	if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
460 		goto nla_put_failure;
461 	spin_unlock_bh(&p->tcf_lock);
462 
463 	kfree(opt);
464 	return skb->len;
465 
466 nla_put_failure:
467 	spin_unlock_bh(&p->tcf_lock);
468 	nlmsg_trim(skb, b);
469 	kfree(opt);
470 	return -1;
471 }
472 
473 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
474 			    struct netlink_callback *cb, int type,
475 			    const struct tc_action_ops *ops,
476 			    struct netlink_ext_ack *extack)
477 {
478 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
479 
480 	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
481 }
482 
483 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
484 {
485 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
486 
487 	return tcf_idr_search(tn, a, index);
488 }
489 
490 static struct tc_action_ops act_pedit_ops = {
491 	.kind		=	"pedit",
492 	.id		=	TCA_ID_PEDIT,
493 	.owner		=	THIS_MODULE,
494 	.act		=	tcf_pedit_act,
495 	.stats_update	=	tcf_pedit_stats_update,
496 	.dump		=	tcf_pedit_dump,
497 	.cleanup	=	tcf_pedit_cleanup,
498 	.init		=	tcf_pedit_init,
499 	.walk		=	tcf_pedit_walker,
500 	.lookup		=	tcf_pedit_search,
501 	.size		=	sizeof(struct tcf_pedit),
502 };
503 
504 static __net_init int pedit_init_net(struct net *net)
505 {
506 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
507 
508 	return tc_action_net_init(net, tn, &act_pedit_ops);
509 }
510 
511 static void __net_exit pedit_exit_net(struct list_head *net_list)
512 {
513 	tc_action_net_exit(net_list, pedit_net_id);
514 }
515 
516 static struct pernet_operations pedit_net_ops = {
517 	.init = pedit_init_net,
518 	.exit_batch = pedit_exit_net,
519 	.id   = &pedit_net_id,
520 	.size = sizeof(struct tc_action_net),
521 };
522 
523 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
524 MODULE_DESCRIPTION("Generic Packet Editor actions");
525 MODULE_LICENSE("GPL");
526 
527 static int __init pedit_init_module(void)
528 {
529 	return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
530 }
531 
532 static void __exit pedit_cleanup_module(void)
533 {
534 	tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
535 }
536 
537 module_init(pedit_init_module);
538 module_exit(pedit_cleanup_module);
539