xref: /openbmc/linux/net/sched/act_pedit.c (revision a0ae2562c6c4b2721d9fddba63b7286c13517d9f) 
1 /*
2  * net/sched/act_pedit.c	Generic packet editor
3  *
4  *		This program is free software; you can redistribute it and/or
5  *		modify it under the terms of the GNU General Public License
6  *		as published by the Free Software Foundation; either version
7  *		2 of the License, or (at your option) any later version.
8  *
9  * Authors:	Jamal Hadi Salim (2002-4)
10  */
11 
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/string.h>
15 #include <linux/errno.h>
16 #include <linux/skbuff.h>
17 #include <linux/rtnetlink.h>
18 #include <linux/module.h>
19 #include <linux/init.h>
20 #include <linux/slab.h>
21 #include <net/netlink.h>
22 #include <net/pkt_sched.h>
23 #include <linux/tc_act/tc_pedit.h>
24 #include <net/tc_act/tc_pedit.h>
25 #include <uapi/linux/tc_act/tc_pedit.h>
26 
27 static unsigned int pedit_net_id;
28 static struct tc_action_ops act_pedit_ops;
29 
30 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
31 	[TCA_PEDIT_PARMS]	= { .len = sizeof(struct tc_pedit) },
32 	[TCA_PEDIT_KEYS_EX]   = { .type = NLA_NESTED },
33 };
34 
35 static const struct nla_policy pedit_key_ex_policy[TCA_PEDIT_KEY_EX_MAX + 1] = {
36 	[TCA_PEDIT_KEY_EX_HTYPE]  = { .type = NLA_U16 },
37 	[TCA_PEDIT_KEY_EX_CMD]	  = { .type = NLA_U16 },
38 };
39 
40 static struct tcf_pedit_key_ex *tcf_pedit_keys_ex_parse(struct nlattr *nla,
41 							u8 n)
42 {
43 	struct tcf_pedit_key_ex *keys_ex;
44 	struct tcf_pedit_key_ex *k;
45 	const struct nlattr *ka;
46 	int err = -EINVAL;
47 	int rem;
48 
49 	if (!nla || !n)
50 		return NULL;
51 
52 	keys_ex = kcalloc(n, sizeof(*k), GFP_KERNEL);
53 	if (!keys_ex)
54 		return ERR_PTR(-ENOMEM);
55 
56 	k = keys_ex;
57 
58 	nla_for_each_nested(ka, nla, rem) {
59 		struct nlattr *tb[TCA_PEDIT_KEY_EX_MAX + 1];
60 
61 		if (!n) {
62 			err = -EINVAL;
63 			goto err_out;
64 		}
65 		n--;
66 
67 		if (nla_type(ka) != TCA_PEDIT_KEY_EX) {
68 			err = -EINVAL;
69 			goto err_out;
70 		}
71 
72 		err = nla_parse_nested(tb, TCA_PEDIT_KEY_EX_MAX, ka,
73 				       pedit_key_ex_policy, NULL);
74 		if (err)
75 			goto err_out;
76 
77 		if (!tb[TCA_PEDIT_KEY_EX_HTYPE] ||
78 		    !tb[TCA_PEDIT_KEY_EX_CMD]) {
79 			err = -EINVAL;
80 			goto err_out;
81 		}
82 
83 		k->htype = nla_get_u16(tb[TCA_PEDIT_KEY_EX_HTYPE]);
84 		k->cmd = nla_get_u16(tb[TCA_PEDIT_KEY_EX_CMD]);
85 
86 		if (k->htype > TCA_PEDIT_HDR_TYPE_MAX ||
87 		    k->cmd > TCA_PEDIT_CMD_MAX) {
88 			err = -EINVAL;
89 			goto err_out;
90 		}
91 
92 		k++;
93 	}
94 
95 	if (n) {
96 		err = -EINVAL;
97 		goto err_out;
98 	}
99 
100 	return keys_ex;
101 
102 err_out:
103 	kfree(keys_ex);
104 	return ERR_PTR(err);
105 }
106 
107 static int tcf_pedit_key_ex_dump(struct sk_buff *skb,
108 				 struct tcf_pedit_key_ex *keys_ex, int n)
109 {
110 	struct nlattr *keys_start = nla_nest_start(skb, TCA_PEDIT_KEYS_EX);
111 
112 	for (; n > 0; n--) {
113 		struct nlattr *key_start;
114 
115 		key_start = nla_nest_start(skb, TCA_PEDIT_KEY_EX);
116 
117 		if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
118 		    nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd)) {
119 			nlmsg_trim(skb, keys_start);
120 			return -EINVAL;
121 		}
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 }
132 
133 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
134 			  struct nlattr *est, struct tc_action **a,
135 			  int ovr, int bind, bool rtnl_held,
136 			  struct netlink_ext_ack *extack)
137 {
138 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
139 	struct nlattr *tb[TCA_PEDIT_MAX + 1];
140 	struct tc_pedit_key *keys = NULL;
141 	struct tcf_pedit_key_ex *keys_ex;
142 	struct tc_pedit *parm;
143 	struct nlattr *pattr;
144 	struct tcf_pedit *p;
145 	int ret = 0, err;
146 	int ksize;
147 
148 	if (!nla) {
149 		NL_SET_ERR_MSG_MOD(extack, "Pedit requires attributes to be passed");
150 		return -EINVAL;
151 	}
152 
153 	err = nla_parse_nested(tb, TCA_PEDIT_MAX, nla, pedit_policy, NULL);
154 	if (err < 0)
155 		return err;
156 
157 	pattr = tb[TCA_PEDIT_PARMS];
158 	if (!pattr)
159 		pattr = tb[TCA_PEDIT_PARMS_EX];
160 	if (!pattr) {
161 		NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
162 		return -EINVAL;
163 	}
164 
165 	parm = nla_data(pattr);
166 	ksize = parm->nkeys * sizeof(struct tc_pedit_key);
167 	if (nla_len(pattr) < sizeof(*parm) + ksize) {
168 		NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
169 		return -EINVAL;
170 	}
171 
172 	keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
173 	if (IS_ERR(keys_ex))
174 		return PTR_ERR(keys_ex);
175 
176 	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
177 	if (!err) {
178 		if (!parm->nkeys) {
179 			tcf_idr_cleanup(tn, parm->index);
180 			NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
181 			ret = -EINVAL;
182 			goto out_free;
183 		}
184 		ret = tcf_idr_create(tn, parm->index, est, a,
185 				     &act_pedit_ops, bind, false);
186 		if (ret) {
187 			tcf_idr_cleanup(tn, parm->index);
188 			goto out_free;
189 		}
190 		p = to_pedit(*a);
191 		keys = kmalloc(ksize, GFP_KERNEL);
192 		if (!keys) {
193 			tcf_idr_release(*a, bind);
194 			ret = -ENOMEM;
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 			tcf_idr_release(*a, bind);
203 			ret = -EEXIST;
204 			goto out_free;
205 		}
206 		p = to_pedit(*a);
207 		if (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys) {
208 			keys = kmalloc(ksize, GFP_KERNEL);
209 			if (!keys) {
210 				ret = -ENOMEM;
211 				goto out_free;
212 			}
213 		}
214 	} else {
215 		return err;
216 	}
217 
218 	spin_lock_bh(&p->tcf_lock);
219 	p->tcfp_flags = parm->flags;
220 	p->tcf_action = parm->action;
221 	if (keys) {
222 		kfree(p->tcfp_keys);
223 		p->tcfp_keys = keys;
224 		p->tcfp_nkeys = parm->nkeys;
225 	}
226 	memcpy(p->tcfp_keys, parm->keys, ksize);
227 
228 	kfree(p->tcfp_keys_ex);
229 	p->tcfp_keys_ex = keys_ex;
230 
231 	spin_unlock_bh(&p->tcf_lock);
232 	if (ret == ACT_P_CREATED)
233 		tcf_idr_insert(tn, *a);
234 	return ret;
235 out_free:
236 	kfree(keys_ex);
237 	return ret;
238 
239 }
240 
241 static void tcf_pedit_cleanup(struct tc_action *a)
242 {
243 	struct tcf_pedit *p = to_pedit(a);
244 	struct tc_pedit_key *keys = p->tcfp_keys;
245 
246 	kfree(keys);
247 	kfree(p->tcfp_keys_ex);
248 }
249 
250 static bool offset_valid(struct sk_buff *skb, int offset)
251 {
252 	if (offset > 0 && offset > skb->len)
253 		return false;
254 
255 	if  (offset < 0 && -offset > skb_headroom(skb))
256 		return false;
257 
258 	return true;
259 }
260 
261 static int pedit_skb_hdr_offset(struct sk_buff *skb,
262 				enum pedit_header_type htype, int *hoffset)
263 {
264 	int ret = -EINVAL;
265 
266 	switch (htype) {
267 	case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
268 		if (skb_mac_header_was_set(skb)) {
269 			*hoffset = skb_mac_offset(skb);
270 			ret = 0;
271 		}
272 		break;
273 	case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
274 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
275 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
276 		*hoffset = skb_network_offset(skb);
277 		ret = 0;
278 		break;
279 	case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
280 	case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
281 		if (skb_transport_header_was_set(skb)) {
282 			*hoffset = skb_transport_offset(skb);
283 			ret = 0;
284 		}
285 		break;
286 	default:
287 		ret = -EINVAL;
288 		break;
289 	};
290 
291 	return ret;
292 }
293 
294 static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
295 		     struct tcf_result *res)
296 {
297 	struct tcf_pedit *p = to_pedit(a);
298 	int i;
299 
300 	if (skb_unclone(skb, GFP_ATOMIC))
301 		return p->tcf_action;
302 
303 	spin_lock(&p->tcf_lock);
304 
305 	tcf_lastuse_update(&p->tcf_tm);
306 
307 	if (p->tcfp_nkeys > 0) {
308 		struct tc_pedit_key *tkey = p->tcfp_keys;
309 		struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
310 		enum pedit_header_type htype =
311 			TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
312 		enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
313 
314 		for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
315 			u32 *ptr, hdata;
316 			int offset = tkey->off;
317 			int hoffset;
318 			u32 val;
319 			int rc;
320 
321 			if (tkey_ex) {
322 				htype = tkey_ex->htype;
323 				cmd = tkey_ex->cmd;
324 
325 				tkey_ex++;
326 			}
327 
328 			rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
329 			if (rc) {
330 				pr_info("tc action pedit bad header type specified (0x%x)\n",
331 					htype);
332 				goto bad;
333 			}
334 
335 			if (tkey->offmask) {
336 				u8 *d, _d;
337 
338 				if (!offset_valid(skb, hoffset + tkey->at)) {
339 					pr_info("tc action pedit 'at' offset %d out of bounds\n",
340 						hoffset + tkey->at);
341 					goto bad;
342 				}
343 				d = skb_header_pointer(skb, hoffset + tkey->at,
344 						       sizeof(_d), &_d);
345 				if (!d)
346 					goto bad;
347 				offset += (*d & tkey->offmask) >> tkey->shift;
348 			}
349 
350 			if (offset % 4) {
351 				pr_info("tc action pedit offset must be on 32 bit boundaries\n");
352 				goto bad;
353 			}
354 
355 			if (!offset_valid(skb, hoffset + offset)) {
356 				pr_info("tc action pedit offset %d out of bounds\n",
357 					hoffset + offset);
358 				goto bad;
359 			}
360 
361 			ptr = skb_header_pointer(skb, hoffset + offset,
362 						 sizeof(hdata), &hdata);
363 			if (!ptr)
364 				goto bad;
365 			/* just do it, baby */
366 			switch (cmd) {
367 			case TCA_PEDIT_KEY_EX_CMD_SET:
368 				val = tkey->val;
369 				break;
370 			case TCA_PEDIT_KEY_EX_CMD_ADD:
371 				val = (*ptr + tkey->val) & ~tkey->mask;
372 				break;
373 			default:
374 				pr_info("tc action pedit bad command (%d)\n",
375 					cmd);
376 				goto bad;
377 			}
378 
379 			*ptr = ((*ptr & tkey->mask) ^ val);
380 			if (ptr == &hdata)
381 				skb_store_bits(skb, hoffset + offset, ptr, 4);
382 		}
383 
384 		goto done;
385 	} else {
386 		WARN(1, "pedit BUG: index %d\n", p->tcf_index);
387 	}
388 
389 bad:
390 	p->tcf_qstats.overlimits++;
391 done:
392 	bstats_update(&p->tcf_bstats, skb);
393 	spin_unlock(&p->tcf_lock);
394 	return p->tcf_action;
395 }
396 
397 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
398 			  int bind, int ref)
399 {
400 	unsigned char *b = skb_tail_pointer(skb);
401 	struct tcf_pedit *p = to_pedit(a);
402 	struct tc_pedit *opt;
403 	struct tcf_t t;
404 	int s;
405 
406 	s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
407 
408 	/* netlink spinlocks held above us - must use ATOMIC */
409 	opt = kzalloc(s, GFP_ATOMIC);
410 	if (unlikely(!opt))
411 		return -ENOBUFS;
412 
413 	memcpy(opt->keys, p->tcfp_keys,
414 	       p->tcfp_nkeys * sizeof(struct tc_pedit_key));
415 	opt->index = p->tcf_index;
416 	opt->nkeys = p->tcfp_nkeys;
417 	opt->flags = p->tcfp_flags;
418 	opt->action = p->tcf_action;
419 	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
420 	opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
421 
422 	if (p->tcfp_keys_ex) {
423 		tcf_pedit_key_ex_dump(skb, p->tcfp_keys_ex, p->tcfp_nkeys);
424 
425 		if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
426 			goto nla_put_failure;
427 	} else {
428 		if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
429 			goto nla_put_failure;
430 	}
431 
432 	tcf_tm_dump(&t, &p->tcf_tm);
433 	if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
434 		goto nla_put_failure;
435 
436 	kfree(opt);
437 	return skb->len;
438 
439 nla_put_failure:
440 	nlmsg_trim(skb, b);
441 	kfree(opt);
442 	return -1;
443 }
444 
445 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
446 			    struct netlink_callback *cb, int type,
447 			    const struct tc_action_ops *ops,
448 			    struct netlink_ext_ack *extack)
449 {
450 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
451 
452 	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
453 }
454 
455 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index,
456 			    struct netlink_ext_ack *extack)
457 {
458 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
459 
460 	return tcf_idr_search(tn, a, index);
461 }
462 
463 static int tcf_pedit_delete(struct net *net, u32 index)
464 {
465 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
466 
467 	return tcf_idr_delete_index(tn, index);
468 }
469 
470 static struct tc_action_ops act_pedit_ops = {
471 	.kind		=	"pedit",
472 	.type		=	TCA_ACT_PEDIT,
473 	.owner		=	THIS_MODULE,
474 	.act		=	tcf_pedit,
475 	.dump		=	tcf_pedit_dump,
476 	.cleanup	=	tcf_pedit_cleanup,
477 	.init		=	tcf_pedit_init,
478 	.walk		=	tcf_pedit_walker,
479 	.lookup		=	tcf_pedit_search,
480 	.delete		=	tcf_pedit_delete,
481 	.size		=	sizeof(struct tcf_pedit),
482 };
483 
484 static __net_init int pedit_init_net(struct net *net)
485 {
486 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
487 
488 	return tc_action_net_init(tn, &act_pedit_ops);
489 }
490 
491 static void __net_exit pedit_exit_net(struct list_head *net_list)
492 {
493 	tc_action_net_exit(net_list, pedit_net_id);
494 }
495 
496 static struct pernet_operations pedit_net_ops = {
497 	.init = pedit_init_net,
498 	.exit_batch = pedit_exit_net,
499 	.id   = &pedit_net_id,
500 	.size = sizeof(struct tc_action_net),
501 };
502 
503 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
504 MODULE_DESCRIPTION("Generic Packet Editor actions");
505 MODULE_LICENSE("GPL");
506 
507 static int __init pedit_init_module(void)
508 {
509 	return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
510 }
511 
512 static void __exit pedit_cleanup_module(void)
513 {
514 	tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
515 }
516 
517 module_init(pedit_init_module);
518 module_exit(pedit_cleanup_module);
519 
520