xref: /openbmc/linux/net/sched/act_pedit.c (revision 53809828) 
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 		return err;
205 	}
206 
207 	p = to_pedit(*a);
208 	spin_lock_bh(&p->tcf_lock);
209 
210 	if (ret == ACT_P_CREATED ||
211 	    (p->tcfp_nkeys && p->tcfp_nkeys != parm->nkeys)) {
212 		keys = kmalloc(ksize, GFP_ATOMIC);
213 		if (!keys) {
214 			spin_unlock_bh(&p->tcf_lock);
215 			ret = -ENOMEM;
216 			goto out_release;
217 		}
218 		kfree(p->tcfp_keys);
219 		p->tcfp_keys = keys;
220 		p->tcfp_nkeys = parm->nkeys;
221 	}
222 	memcpy(p->tcfp_keys, parm->keys, ksize);
223 
224 	p->tcfp_flags = parm->flags;
225 	p->tcf_action = parm->action;
226 
227 	kfree(p->tcfp_keys_ex);
228 	p->tcfp_keys_ex = keys_ex;
229 
230 	spin_unlock_bh(&p->tcf_lock);
231 	if (ret == ACT_P_CREATED)
232 		tcf_idr_insert(tn, *a);
233 	return ret;
234 
235 out_release:
236 	tcf_idr_release(*a, bind);
237 out_free:
238 	kfree(keys_ex);
239 	return ret;
240 
241 }
242 
243 static void tcf_pedit_cleanup(struct tc_action *a)
244 {
245 	struct tcf_pedit *p = to_pedit(a);
246 	struct tc_pedit_key *keys = p->tcfp_keys;
247 
248 	kfree(keys);
249 	kfree(p->tcfp_keys_ex);
250 }
251 
252 static bool offset_valid(struct sk_buff *skb, int offset)
253 {
254 	if (offset > 0 && offset > skb->len)
255 		return false;
256 
257 	if  (offset < 0 && -offset > skb_headroom(skb))
258 		return false;
259 
260 	return true;
261 }
262 
263 static int pedit_skb_hdr_offset(struct sk_buff *skb,
264 				enum pedit_header_type htype, int *hoffset)
265 {
266 	int ret = -EINVAL;
267 
268 	switch (htype) {
269 	case TCA_PEDIT_KEY_EX_HDR_TYPE_ETH:
270 		if (skb_mac_header_was_set(skb)) {
271 			*hoffset = skb_mac_offset(skb);
272 			ret = 0;
273 		}
274 		break;
275 	case TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK:
276 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP4:
277 	case TCA_PEDIT_KEY_EX_HDR_TYPE_IP6:
278 		*hoffset = skb_network_offset(skb);
279 		ret = 0;
280 		break;
281 	case TCA_PEDIT_KEY_EX_HDR_TYPE_TCP:
282 	case TCA_PEDIT_KEY_EX_HDR_TYPE_UDP:
283 		if (skb_transport_header_was_set(skb)) {
284 			*hoffset = skb_transport_offset(skb);
285 			ret = 0;
286 		}
287 		break;
288 	default:
289 		ret = -EINVAL;
290 		break;
291 	}
292 
293 	return ret;
294 }
295 
296 static int tcf_pedit_act(struct sk_buff *skb, const struct tc_action *a,
297 			 struct tcf_result *res)
298 {
299 	struct tcf_pedit *p = to_pedit(a);
300 	int i;
301 
302 	if (skb_unclone(skb, GFP_ATOMIC))
303 		return p->tcf_action;
304 
305 	spin_lock(&p->tcf_lock);
306 
307 	tcf_lastuse_update(&p->tcf_tm);
308 
309 	if (p->tcfp_nkeys > 0) {
310 		struct tc_pedit_key *tkey = p->tcfp_keys;
311 		struct tcf_pedit_key_ex *tkey_ex = p->tcfp_keys_ex;
312 		enum pedit_header_type htype =
313 			TCA_PEDIT_KEY_EX_HDR_TYPE_NETWORK;
314 		enum pedit_cmd cmd = TCA_PEDIT_KEY_EX_CMD_SET;
315 
316 		for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
317 			u32 *ptr, hdata;
318 			int offset = tkey->off;
319 			int hoffset;
320 			u32 val;
321 			int rc;
322 
323 			if (tkey_ex) {
324 				htype = tkey_ex->htype;
325 				cmd = tkey_ex->cmd;
326 
327 				tkey_ex++;
328 			}
329 
330 			rc = pedit_skb_hdr_offset(skb, htype, &hoffset);
331 			if (rc) {
332 				pr_info("tc action pedit bad header type specified (0x%x)\n",
333 					htype);
334 				goto bad;
335 			}
336 
337 			if (tkey->offmask) {
338 				u8 *d, _d;
339 
340 				if (!offset_valid(skb, hoffset + tkey->at)) {
341 					pr_info("tc action pedit 'at' offset %d out of bounds\n",
342 						hoffset + tkey->at);
343 					goto bad;
344 				}
345 				d = skb_header_pointer(skb, hoffset + tkey->at,
346 						       sizeof(_d), &_d);
347 				if (!d)
348 					goto bad;
349 				offset += (*d & tkey->offmask) >> tkey->shift;
350 			}
351 
352 			if (offset % 4) {
353 				pr_info("tc action pedit offset must be on 32 bit boundaries\n");
354 				goto bad;
355 			}
356 
357 			if (!offset_valid(skb, hoffset + offset)) {
358 				pr_info("tc action pedit offset %d out of bounds\n",
359 					hoffset + offset);
360 				goto bad;
361 			}
362 
363 			ptr = skb_header_pointer(skb, hoffset + offset,
364 						 sizeof(hdata), &hdata);
365 			if (!ptr)
366 				goto bad;
367 			/* just do it, baby */
368 			switch (cmd) {
369 			case TCA_PEDIT_KEY_EX_CMD_SET:
370 				val = tkey->val;
371 				break;
372 			case TCA_PEDIT_KEY_EX_CMD_ADD:
373 				val = (*ptr + tkey->val) & ~tkey->mask;
374 				break;
375 			default:
376 				pr_info("tc action pedit bad command (%d)\n",
377 					cmd);
378 				goto bad;
379 			}
380 
381 			*ptr = ((*ptr & tkey->mask) ^ val);
382 			if (ptr == &hdata)
383 				skb_store_bits(skb, hoffset + offset, ptr, 4);
384 		}
385 
386 		goto done;
387 	} else {
388 		WARN(1, "pedit BUG: index %d\n", p->tcf_index);
389 	}
390 
391 bad:
392 	p->tcf_qstats.overlimits++;
393 done:
394 	bstats_update(&p->tcf_bstats, skb);
395 	spin_unlock(&p->tcf_lock);
396 	return p->tcf_action;
397 }
398 
399 static int tcf_pedit_dump(struct sk_buff *skb, struct tc_action *a,
400 			  int bind, int ref)
401 {
402 	unsigned char *b = skb_tail_pointer(skb);
403 	struct tcf_pedit *p = to_pedit(a);
404 	struct tc_pedit *opt;
405 	struct tcf_t t;
406 	int s;
407 
408 	s = sizeof(*opt) + p->tcfp_nkeys * sizeof(struct tc_pedit_key);
409 
410 	/* netlink spinlocks held above us - must use ATOMIC */
411 	opt = kzalloc(s, GFP_ATOMIC);
412 	if (unlikely(!opt))
413 		return -ENOBUFS;
414 
415 	spin_lock_bh(&p->tcf_lock);
416 	memcpy(opt->keys, p->tcfp_keys,
417 	       p->tcfp_nkeys * sizeof(struct tc_pedit_key));
418 	opt->index = p->tcf_index;
419 	opt->nkeys = p->tcfp_nkeys;
420 	opt->flags = p->tcfp_flags;
421 	opt->action = p->tcf_action;
422 	opt->refcnt = refcount_read(&p->tcf_refcnt) - ref;
423 	opt->bindcnt = atomic_read(&p->tcf_bindcnt) - bind;
424 
425 	if (p->tcfp_keys_ex) {
426 		if (tcf_pedit_key_ex_dump(skb,
427 					  p->tcfp_keys_ex,
428 					  p->tcfp_nkeys))
429 			goto nla_put_failure;
430 
431 		if (nla_put(skb, TCA_PEDIT_PARMS_EX, s, opt))
432 			goto nla_put_failure;
433 	} else {
434 		if (nla_put(skb, TCA_PEDIT_PARMS, s, opt))
435 			goto nla_put_failure;
436 	}
437 
438 	tcf_tm_dump(&t, &p->tcf_tm);
439 	if (nla_put_64bit(skb, TCA_PEDIT_TM, sizeof(t), &t, TCA_PEDIT_PAD))
440 		goto nla_put_failure;
441 	spin_unlock_bh(&p->tcf_lock);
442 
443 	kfree(opt);
444 	return skb->len;
445 
446 nla_put_failure:
447 	spin_unlock_bh(&p->tcf_lock);
448 	nlmsg_trim(skb, b);
449 	kfree(opt);
450 	return -1;
451 }
452 
453 static int tcf_pedit_walker(struct net *net, struct sk_buff *skb,
454 			    struct netlink_callback *cb, int type,
455 			    const struct tc_action_ops *ops,
456 			    struct netlink_ext_ack *extack)
457 {
458 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
459 
460 	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
461 }
462 
463 static int tcf_pedit_search(struct net *net, struct tc_action **a, u32 index)
464 {
465 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
466 
467 	return tcf_idr_search(tn, a, 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_act,
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 	.size		=	sizeof(struct tcf_pedit),
481 };
482 
483 static __net_init int pedit_init_net(struct net *net)
484 {
485 	struct tc_action_net *tn = net_generic(net, pedit_net_id);
486 
487 	return tc_action_net_init(tn, &act_pedit_ops);
488 }
489 
490 static void __net_exit pedit_exit_net(struct list_head *net_list)
491 {
492 	tc_action_net_exit(net_list, pedit_net_id);
493 }
494 
495 static struct pernet_operations pedit_net_ops = {
496 	.init = pedit_init_net,
497 	.exit_batch = pedit_exit_net,
498 	.id   = &pedit_net_id,
499 	.size = sizeof(struct tc_action_net),
500 };
501 
502 MODULE_AUTHOR("Jamal Hadi Salim(2002-4)");
503 MODULE_DESCRIPTION("Generic Packet Editor actions");
504 MODULE_LICENSE("GPL");
505 
506 static int __init pedit_init_module(void)
507 {
508 	return tcf_register_action(&act_pedit_ops, &pedit_net_ops);
509 }
510 
511 static void __exit pedit_cleanup_module(void)
512 {
513 	tcf_unregister_action(&act_pedit_ops, &pedit_net_ops);
514 }
515 
516 module_init(pedit_init_module);
517 module_exit(pedit_cleanup_module);
518