xref: /openbmc/linux/net/sched/act_pedit.c (revision d0e22329) 
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 	if (!keys_start)
113 		goto nla_failure;
114 	for (; n > 0; n--) {
115 		struct nlattr *key_start;
116 
117 		key_start = nla_nest_start(skb, TCA_PEDIT_KEY_EX);
118 		if (!key_start)
119 			goto nla_failure;
120 
121 		if (nla_put_u16(skb, TCA_PEDIT_KEY_EX_HTYPE, keys_ex->htype) ||
122 		    nla_put_u16(skb, TCA_PEDIT_KEY_EX_CMD, keys_ex->cmd))
123 			goto nla_failure;
124 
125 		nla_nest_end(skb, key_start);
126 
127 		keys_ex++;
128 	}
129 
130 	nla_nest_end(skb, keys_start);
131 
132 	return 0;
133 nla_failure:
134 	nla_nest_cancel(skb, keys_start);
135 	return -EINVAL;
136 }
137 
138 static int tcf_pedit_init(struct net *net, struct nlattr *nla,
139 			  struct nlattr *est, struct tc_action **a,
140 			  int ovr, int bind, bool rtnl_held,
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 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(tb, TCA_PEDIT_MAX, nla, pedit_policy, NULL);
159 	if (err < 0)
160 		return err;
161 
162 	pattr = tb[TCA_PEDIT_PARMS];
163 	if (!pattr)
164 		pattr = tb[TCA_PEDIT_PARMS_EX];
165 	if (!pattr) {
166 		NL_SET_ERR_MSG_MOD(extack, "Missing required TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute");
167 		return -EINVAL;
168 	}
169 
170 	parm = nla_data(pattr);
171 	ksize = parm->nkeys * sizeof(struct tc_pedit_key);
172 	if (nla_len(pattr) < sizeof(*parm) + ksize) {
173 		NL_SET_ERR_MSG_ATTR(extack, pattr, "Length of TCA_PEDIT_PARMS or TCA_PEDIT_PARMS_EX pedit attribute is invalid");
174 		return -EINVAL;
175 	}
176 
177 	keys_ex = tcf_pedit_keys_ex_parse(tb[TCA_PEDIT_KEYS_EX], parm->nkeys);
178 	if (IS_ERR(keys_ex))
179 		return PTR_ERR(keys_ex);
180 
181 	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
182 	if (!err) {
183 		if (!parm->nkeys) {
184 			tcf_idr_cleanup(tn, parm->index);
185 			NL_SET_ERR_MSG_MOD(extack, "Pedit requires keys to be passed");
186 			ret = -EINVAL;
187 			goto out_free;
188 		}
189 		ret = tcf_idr_create(tn, parm->index, est, a,
190 				     &act_pedit_ops, bind, false);
191 		if (ret) {
192 			tcf_idr_cleanup(tn, parm->index);
193 			goto out_free;
194 		}
195 		ret = ACT_P_CREATED;
196 	} else if (err > 0) {
197 		if (bind)
198 			goto out_free;
199 		if (!ovr) {
200 			ret = -EEXIST;
201 			goto out_release;
202 		}
203 	} else {
204 		ret = err;
205 		goto out_free;
206 	}
207 
208 	p = to_pedit(*a);
209 	spin_lock_bh(&p->tcf_lock);
210 
211 	if (ret == ACT_P_CREATED ||
212 	    (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
213 		keys = kmalloc(ksize, GFP_ATOMIC);
214 		if (!keys) {
215 			spin_unlock_bh(&p->tcf_lock);
216 			ret = -ENOMEM;
217 			goto out_release;
218 		}
219 		kfree(p->tcfp_keys);
220 		p->tcfp_keys = keys;
221 		p->tcfp_nkeys = parm->nkeys;
222 	}
223 	memcpy(p->tcfp_keys, parm->keys, ksize);
224 
225 	p->tcfp_flags = parm->flags;
226 	p->tcf_action = parm->action;
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 
236 out_release:
237 	tcf_idr_release(*a, bind);
238 out_free:
239 	kfree(keys_ex);
240 	return ret;
241 
242 }
243 
244 static void tcf_pedit_cleanup(struct tc_action *a)
245 {
246 	struct tcf_pedit *p = to_pedit(a);
247 	struct tc_pedit_key *keys = p->tcfp_keys;
248 
249 	kfree(keys);
250 	kfree(p->tcfp_keys_ex);
251 }
252 
253 static bool offset_valid(struct sk_buff *skb, int offset)
254 {
255 	if (offset > 0 && offset > skb->len)
256 		return false;
257 
258 	if  (offset < 0 && -offset > skb_headroom(skb))
259 		return false;
260 
261 	return true;
262 }
263 
264 static int pedit_skb_hdr_offset(struct sk_buff *skb,
265 				enum pedit_header_type htype, int *hoffset)
266 {
267 	int ret = -EINVAL;
268 
269 	switch (htype) {
270 	case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
271 		if (skb_mac_header_was_set(skb)) {
272 			*hoffset = skb_mac_offset(skb);
273 			ret = 0;
274 		}
275 		break;
276 	case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
277 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
278 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
279 		*hoffset = skb_network_offset(skb);
280 		ret = 0;
281 		break;
282 	case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
283 	case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
284 		if (skb_transport_header_was_set(skb)) {
285 			*hoffset = skb_transport_offset(skb);
286 			ret = 0;
287 		}
288 		break;
289 	default:
290 		ret = -EINVAL;
291 		break;
292 	}
293 
294 	return ret;
295 }
296 
297 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
298 			 struct tcf_result *res)
299 {
300 	struct tcf_pedit *p = to_pedit(a);
301 	int i;
302 
303 	if (skb_unclone(skb, GFP_ATOMIC))
304 		return p->tcf_action;
305 
306 	spin_lock(&p->tcf_lock);
307 
308 	tcf_lastuse_update(&p->tcf_tm);
309 
310 	if (p->tcfp_nkeys > 0) {
311 		struct tc_pedit_key *tkey = p->tcfp_keys;
312 		struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
313 		enum pedit_header_type htype =
314 			TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
315 		enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
316 
317 		for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
318 			u32 *ptr, hdata;
319 			int offset = tkey->off;
320 			int hoffset;
321 			u32 val;
322 			int rc;
323 
324 			if (tkey_ex) {
325 				htype = tkey_ex->htype;
326 				cmd = tkey_ex->cmd;
327 
328 				tkey_ex++;
329 			}
330 
331 			rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
332 			if (rc) {
333 				pr_info("tc action pedit bad header type specified (0x%x)\n",
334 					htype);
335 				goto bad;
336 			}
337 
338 			if (tkey->offmask) {
339 				u8 *d, _d;
340 
341 				if (!offset_valid(skb, hoffset + tkey->at)) {
342 					pr_info("tc action pedit 'at' offset %d out of bounds\n",
343 						hoffset + tkey->at);
344 					goto bad;
345 				}
346 				d = skb_header_pointer(skb, hoffset + tkey->at,
347 						       sizeof(_d), &_d);
348 				if (!d)
349 					goto bad;
350 				offset += (*d & tkey->offmask) >> tkey->shift;
351 			}
352 
353 			if (offset % 4) {
354 				pr_info("tc action pedit offset must be on 32 bit boundaries\n");
355 				goto bad;
356 			}
357 
358 			if (!offset_valid(skb, hoffset + offset)) {
359 				pr_info("tc action pedit offset %d out of bounds\n",
360 					hoffset + offset);
361 				goto bad;
362 			}
363 
364 			ptr = skb_header_pointer(skb, hoffset + offset,
365 						 sizeof(hdata), &hdata);
366 			if (!ptr)
367 				goto bad;
368 			/* just do it, baby */
369 			switch (cmd) {
370 			case TCA_PEDIT_KEY_EX_CMD_SET:
371 				val = tkey->val;
372 				break;
373 			case TCA_PEDIT_KEY_EX_CMD_ADD:
374 				val = (*ptr + tkey->val) & ~tkey->mask;
375 				break;
376 			default:
377 				pr_info("tc action pedit bad command (%d)\n",
378 					cmd);
379 				goto bad;
380 			}
381 
382 			*ptr = ((*ptr & tkey->mask) ^ val);
383 			if (ptr == &hdata)
384 				skb_store_bits(skb, hoffset + offset, ptr, 4);
385 		}
386 
387 		goto done;
388 	} else {
389 		WARN(1, "pedit BUG: index %d\n", p->tcf_index);
390 	}
391 
392 bad:
393 	p->tcf_qstats.overlimits++;
394 done:
395 	bstats_update(&p->tcf_bstats, skb);
396 	spin_unlock(&p->tcf_lock);
397 	return p->tcf_action;
398 }
399 
400 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
401 			  int bind, int ref)
402 {
403 	unsigned char *b = skb_tail_pointer(skb);
404 	struct tcf_pedit *p = to_pedit(a);
405 	struct tc_pedit *opt;
406 	struct tcf_t t;
407 	int s;
408 
409 	s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
410 
411 	/* netlink spinlocks held above us - must use ATOMIC */
412 	opt = kzalloc(s, GFP_ATOMIC);
413 	if (unlikely(!opt))
414 		return -ENOBUFS;
415 
416 	spin_lock_bh(&p->tcf_lock);
417 	memcpy(opt->keys, p->tcfp_keys,
418 	       p->tcfp_nkeys * sizeof(struct tc_pedit_key));
419 	opt->index = p->tcf_index;
420 	opt->nkeys = p->tcfp_nkeys;
421 	opt->flags = p->tcfp_flags;
422 	opt->action = p->tcf_action;
423 	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
424 	opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
425 
426 	if (p->tcfp_keys_ex) {
427 		if (tcf_pedit_key_ex_dump(skb,
428 					  p->tcfp_keys_ex,
429 					  p->tcfp_nkeys))
430 			goto nla_put_failure;
431 
432 		if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
433 			goto nla_put_failure;
434 	} else {
435 		if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
436 			goto nla_put_failure;
437 	}
438 
439 	tcf_tm_dump(&t, &p->tcf_tm);
440 	if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
441 		goto nla_put_failure;
442 	spin_unlock_bh(&p->tcf_lock);
443 
444 	kfree(opt);
445 	return skb->len;
446 
447 nla_put_failure:
448 	spin_unlock_bh(&p->tcf_lock);
449 	nlmsg_trim(skb, b);
450 	kfree(opt);
451 	return -1;
452 }
453 
454 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
455 			    struct netlink_callback *cb, int type,
456 			    const struct tc_action_ops *ops,
457 			    struct netlink_ext_ack *extack)
458 {
459 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
460 
461 	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
462 }
463 
464 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
465 {
466 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
467 
468 	return tcf_idr_search(tn, a, index);
469 }
470 
471 static struct tc_action_ops act_pedit_ops = {
472 	.kind		=	"pedit",
473 	.type		=	TCA_ACT_PEDIT,
474 	.owner		=	THIS_MODULE,
475 	.act		=	tcf_pedit_act,
476 	.dump		=	tcf_pedit_dump,
477 	.cleanup	=	tcf_pedit_cleanup,
478 	.init		=	tcf_pedit_init,
479 	.walk		=	tcf_pedit_walker,
480 	.lookup		=	tcf_pedit_search,
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