xref: /openbmc/linux/net/sched/act_pedit.c (revision b8d312aa) 
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 || !n)
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, struct netlink_ext_ack *extack)
141 {
142 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
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 ksize;
152 
153 	if (!nla) {
154 		NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
155 		return -EINVAL;
156 	}
157 
158 	err = nla_parse_nested_deprecated(tb, TCA_PEDIT_MAX, nla,
159 					  pedit_policy, NULL);
160 	if (err < 0)
161 		return err;
162 
163 	pattr = tb[TCA_PEDIT_PARMS];
164 	if (!pattr)
165 		pattr = tb[TCA_PEDIT_PARMS_EX];
166 	if (!pattr) {
167 		NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
168 		return -EINVAL;
169 	}
170 
171 	parm = nla_data(pattr);
172 	ksize = parm->nkeys * sizeof(struct tc_pedit_key);
173 	if (nla_len(pattr) < sizeof(*parm) + ksize) {
174 		NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
175 		return -EINVAL;
176 	}
177 
178 	keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
179 	if (IS_ERR(keys_ex))
180 		return PTR_ERR(keys_ex);
181 
182 	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
183 	if (!err) {
184 		if (!parm->nkeys) {
185 			tcf_idr_cleanup(tn, parm->index);
186 			NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
187 			ret = -EINVAL;
188 			goto out_free;
189 		}
190 		ret = tcf_idr_create(tn, parm->index, est, a,
191 				     &act_pedit_ops, bind, false);
192 		if (ret) {
193 			tcf_idr_cleanup(tn, parm->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 (!ovr) {
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 
231 	p->tcfp_flags = parm->flags;
232 	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
233 
234 	kfree(p->tcfp_keys_ex);
235 	p->tcfp_keys_ex = keys_ex;
236 
237 	spin_unlock_bh(&p->tcf_lock);
238 	if (goto_ch)
239 		tcf_chain_put_by_act(goto_ch);
240 	if (ret == ACT_P_CREATED)
241 		tcf_idr_insert(tn, *a);
242 	return ret;
243 
244 put_chain:
245 	if (goto_ch)
246 		tcf_chain_put_by_act(goto_ch);
247 out_release:
248 	tcf_idr_release(*a, bind);
249 out_free:
250 	kfree(keys_ex);
251 	return ret;
252 
253 }
254 
255 static void tcf_pedit_cleanup(struct tc_action *a)
256 {
257 	struct tcf_pedit *p = to_pedit(a);
258 	struct tc_pedit_key *keys = p->tcfp_keys;
259 
260 	kfree(keys);
261 	kfree(p->tcfp_keys_ex);
262 }
263 
264 static bool offset_valid(struct sk_buff *skb, int offset)
265 {
266 	if (offset > 0 && offset > skb->len)
267 		return false;
268 
269 	if  (offset < 0 && -offset > skb_headroom(skb))
270 		return false;
271 
272 	return true;
273 }
274 
275 static int pedit_skb_hdr_offset(struct sk_buff *skb,
276 				enum pedit_header_type htype, int *hoffset)
277 {
278 	int ret = -EINVAL;
279 
280 	switch (htype) {
281 	case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
282 		if (skb_mac_header_was_set(skb)) {
283 			*hoffset = skb_mac_offset(skb);
284 			ret = 0;
285 		}
286 		break;
287 	case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
288 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
289 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
290 		*hoffset = skb_network_offset(skb);
291 		ret = 0;
292 		break;
293 	case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
294 	case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
295 		if (skb_transport_header_was_set(skb)) {
296 			*hoffset = skb_transport_offset(skb);
297 			ret = 0;
298 		}
299 		break;
300 	default:
301 		ret = -EINVAL;
302 		break;
303 	}
304 
305 	return ret;
306 }
307 
308 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
309 			 struct tcf_result *res)
310 {
311 	struct tcf_pedit *p = to_pedit(a);
312 	int i;
313 
314 	if (skb_unclone(skb, GFP_ATOMIC))
315 		return p->tcf_action;
316 
317 	spin_lock(&p->tcf_lock);
318 
319 	tcf_lastuse_update(&p->tcf_tm);
320 
321 	if (p->tcfp_nkeys > 0) {
322 		struct tc_pedit_key *tkey = p->tcfp_keys;
323 		struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
324 		enum pedit_header_type htype =
325 			TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
326 		enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
327 
328 		for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
329 			u32 *ptr, hdata;
330 			int offset = tkey->off;
331 			int hoffset;
332 			u32 val;
333 			int rc;
334 
335 			if (tkey_ex) {
336 				htype = tkey_ex->htype;
337 				cmd = tkey_ex->cmd;
338 
339 				tkey_ex++;
340 			}
341 
342 			rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
343 			if (rc) {
344 				pr_info("tc action pedit bad header type specified (0x%x)\n",
345 					htype);
346 				goto bad;
347 			}
348 
349 			if (tkey->offmask) {
350 				u8 *d, _d;
351 
352 				if (!offset_valid(skb, hoffset + tkey->at)) {
353 					pr_info("tc action pedit 'at' offset %d out of bounds\n",
354 						hoffset + tkey->at);
355 					goto bad;
356 				}
357 				d = skb_header_pointer(skb, hoffset + tkey->at,
358 						       sizeof(_d), &_d);
359 				if (!d)
360 					goto bad;
361 				offset += (*d & tkey->offmask) >> tkey->shift;
362 			}
363 
364 			if (offset % 4) {
365 				pr_info("tc action pedit offset must be on 32 bit boundaries\n");
366 				goto bad;
367 			}
368 
369 			if (!offset_valid(skb, hoffset + offset)) {
370 				pr_info("tc action pedit offset %d out of bounds\n",
371 					hoffset + offset);
372 				goto bad;
373 			}
374 
375 			ptr = skb_header_pointer(skb, hoffset + offset,
376 						 sizeof(hdata), &hdata);
377 			if (!ptr)
378 				goto bad;
379 			/* just do it, baby */
380 			switch (cmd) {
381 			case TCA_PEDIT_KEY_EX_CMD_SET:
382 				val = tkey->val;
383 				break;
384 			case TCA_PEDIT_KEY_EX_CMD_ADD:
385 				val = (*ptr + tkey->val) & ~tkey->mask;
386 				break;
387 			default:
388 				pr_info("tc action pedit bad command (%d)\n",
389 					cmd);
390 				goto bad;
391 			}
392 
393 			*ptr = ((*ptr & tkey->mask) ^ val);
394 			if (ptr == &hdata)
395 				skb_store_bits(skb, hoffset + offset, ptr, 4);
396 		}
397 
398 		goto done;
399 	} else {
400 		WARN(1, "pedit BUG: index %d\n", p->tcf_index);
401 	}
402 
403 bad:
404 	p->tcf_qstats.overlimits++;
405 done:
406 	bstats_update(&p->tcf_bstats, skb);
407 	spin_unlock(&p->tcf_lock);
408 	return p->tcf_action;
409 }
410 
411 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
412 			  int bind, int ref)
413 {
414 	unsigned char *b = skb_tail_pointer(skb);
415 	struct tcf_pedit *p = to_pedit(a);
416 	struct tc_pedit *opt;
417 	struct tcf_t t;
418 	int s;
419 
420 	s = struct_size(opt, keys, p->tcfp_nkeys);
421 
422 	/* netlink spinlocks held above us - must use ATOMIC */
423 	opt = kzalloc(s, GFP_ATOMIC);
424 	if (unlikely(!opt))
425 		return -ENOBUFS;
426 
427 	spin_lock_bh(&p->tcf_lock);
428 	memcpy(opt->keys, p->tcfp_keys,
429 	       p->tcfp_nkeys * sizeof(struct tc_pedit_key));
430 	opt->index = p->tcf_index;
431 	opt->nkeys = p->tcfp_nkeys;
432 	opt->flags = p->tcfp_flags;
433 	opt->action = p->tcf_action;
434 	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
435 	opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
436 
437 	if (p->tcfp_keys_ex) {
438 		if (tcf_pedit_key_ex_dump(skb,
439 					  p->tcfp_keys_ex,
440 					  p->tcfp_nkeys))
441 			goto nla_put_failure;
442 
443 		if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
444 			goto nla_put_failure;
445 	} else {
446 		if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
447 			goto nla_put_failure;
448 	}
449 
450 	tcf_tm_dump(&t, &p->tcf_tm);
451 	if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
452 		goto nla_put_failure;
453 	spin_unlock_bh(&p->tcf_lock);
454 
455 	kfree(opt);
456 	return skb->len;
457 
458 nla_put_failure:
459 	spin_unlock_bh(&p->tcf_lock);
460 	nlmsg_trim(skb, b);
461 	kfree(opt);
462 	return -1;
463 }
464 
465 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
466 			    struct netlink_callback *cb, int type,
467 			    const struct tc_action_ops *ops,
468 			    struct netlink_ext_ack *extack)
469 {
470 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
471 
472 	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
473 }
474 
475 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
476 {
477 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
478 
479 	return tcf_idr_search(tn, a, index);
480 }
481 
482 static struct tc_action_ops act_pedit_ops = {
483 	.kind		=	"pedit",
484 	.id		=	TCA_ID_PEDIT,
485 	.owner		=	THIS_MODULE,
486 	.act		=	tcf_pedit_act,
487 	.dump		=	tcf_pedit_dump,
488 	.cleanup	=	tcf_pedit_cleanup,
489 	.init		=	tcf_pedit_init,
490 	.walk		=	tcf_pedit_walker,
491 	.lookup		=	tcf_pedit_search,
492 	.size		=	sizeof(struct tcf_pedit),
493 };
494 
495 static __net_init int pedit_init_net(struct net *net)
496 {
497 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
498 
499 	return tc_action_net_init(tn, &act_pedit_ops);
500 }
501 
502 static void __net_exit pedit_exit_net(struct list_head *net_list)
503 {
504 	tc_action_net_exit(net_list, pedit_net_id);
505 }
506 
507 static struct pernet_operations pedit_net_ops = {
508 	.init = pedit_init_net,
509 	.exit_batch = pedit_exit_net,
510 	.id   = &pedit_net_id,
511 	.size = sizeof(struct tc_action_net),
512 };
513 
514 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
515 MODULE_DESCRIPTION("Generic Packet Editor actions");
516 MODULE_LICENSE("GPL");
517 
518 static int __init pedit_init_module(void)
519 {
520 	return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
521 }
522 
523 static void __exit pedit_cleanup_module(void)
524 {
525 	tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
526 }
527 
528 module_init(pedit_init_module);
529 module_exit(pedit_cleanup_module);
530