xref: /linux/net/sched/act_ife.c (revision 2bc46b3ad3c15165f91459b07ff8682478683194)
1 /*
2  * net/sched/ife.c	Inter-FE action based on ForCES WG InterFE LFB
3  *
4  *		Refer to:
5  *		draft-ietf-forces-interfelfb-03
6  *		and
7  *		netdev01 paper:
8  *		"Distributing Linux Traffic Control Classifier-Action
9  *		Subsystem"
10  *		Authors: Jamal Hadi Salim and Damascene M. Joachimpillai
11  *
12  *		This program is free software; you can redistribute it and/or
13  *		modify it under the terms of the GNU General Public License
14  *		as published by the Free Software Foundation; either version
15  *		2 of the License, or (at your option) any later version.
16  *
17  * copyright Jamal Hadi Salim (2015)
18  *
19 */
20 
21 #include <linux/types.h>
22 #include <linux/kernel.h>
23 #include <linux/string.h>
24 #include <linux/errno.h>
25 #include <linux/skbuff.h>
26 #include <linux/rtnetlink.h>
27 #include <linux/module.h>
28 #include <linux/init.h>
29 #include <net/net_namespace.h>
30 #include <net/netlink.h>
31 #include <net/pkt_sched.h>
32 #include <uapi/linux/tc_act/tc_ife.h>
33 #include <net/tc_act/tc_ife.h>
34 #include <linux/etherdevice.h>
35 
36 #define IFE_TAB_MASK 15
37 
38 static int ife_net_id;
39 static int max_metacnt = IFE_META_MAX + 1;
40 
41 static const struct nla_policy ife_policy[TCA_IFE_MAX + 1] = {
42 	[TCA_IFE_PARMS] = { .len = sizeof(struct tc_ife)},
43 	[TCA_IFE_DMAC] = { .len = ETH_ALEN},
44 	[TCA_IFE_SMAC] = { .len = ETH_ALEN},
45 	[TCA_IFE_TYPE] = { .type = NLA_U16},
46 };
47 
48 /* Caller takes care of presenting data in network order
49 */
50 int ife_tlv_meta_encode(void *skbdata, u16 attrtype, u16 dlen, const void *dval)
51 {
52 	u32 *tlv = (u32 *)(skbdata);
53 	u16 totlen = nla_total_size(dlen);	/*alignment + hdr */
54 	char *dptr = (char *)tlv + NLA_HDRLEN;
55 	u32 htlv = attrtype << 16 | totlen;
56 
57 	*tlv = htonl(htlv);
58 	memset(dptr, 0, totlen - NLA_HDRLEN);
59 	memcpy(dptr, dval, dlen);
60 
61 	return totlen;
62 }
63 EXPORT_SYMBOL_GPL(ife_tlv_meta_encode);
64 
65 int ife_get_meta_u32(struct sk_buff *skb, struct tcf_meta_info *mi)
66 {
67 	if (mi->metaval)
68 		return nla_put_u32(skb, mi->metaid, *(u32 *)mi->metaval);
69 	else
70 		return nla_put(skb, mi->metaid, 0, NULL);
71 }
72 EXPORT_SYMBOL_GPL(ife_get_meta_u32);
73 
74 int ife_check_meta_u32(u32 metaval, struct tcf_meta_info *mi)
75 {
76 	if (metaval || mi->metaval)
77 		return 8; /* T+L+V == 2+2+4 */
78 
79 	return 0;
80 }
81 EXPORT_SYMBOL_GPL(ife_check_meta_u32);
82 
83 int ife_encode_meta_u32(u32 metaval, void *skbdata, struct tcf_meta_info *mi)
84 {
85 	u32 edata = metaval;
86 
87 	if (mi->metaval)
88 		edata = *(u32 *)mi->metaval;
89 	else if (metaval)
90 		edata = metaval;
91 
92 	if (!edata) /* will not encode */
93 		return 0;
94 
95 	edata = htonl(edata);
96 	return ife_tlv_meta_encode(skbdata, mi->metaid, 4, &edata);
97 }
98 EXPORT_SYMBOL_GPL(ife_encode_meta_u32);
99 
100 int ife_get_meta_u16(struct sk_buff *skb, struct tcf_meta_info *mi)
101 {
102 	if (mi->metaval)
103 		return nla_put_u16(skb, mi->metaid, *(u16 *)mi->metaval);
104 	else
105 		return nla_put(skb, mi->metaid, 0, NULL);
106 }
107 EXPORT_SYMBOL_GPL(ife_get_meta_u16);
108 
109 int ife_alloc_meta_u32(struct tcf_meta_info *mi, void *metaval)
110 {
111 	mi->metaval = kmemdup(metaval, sizeof(u32), GFP_KERNEL);
112 	if (!mi->metaval)
113 		return -ENOMEM;
114 
115 	return 0;
116 }
117 EXPORT_SYMBOL_GPL(ife_alloc_meta_u32);
118 
119 int ife_alloc_meta_u16(struct tcf_meta_info *mi, void *metaval)
120 {
121 	mi->metaval = kmemdup(metaval, sizeof(u16), GFP_KERNEL);
122 	if (!mi->metaval)
123 		return -ENOMEM;
124 
125 	return 0;
126 }
127 EXPORT_SYMBOL_GPL(ife_alloc_meta_u16);
128 
129 void ife_release_meta_gen(struct tcf_meta_info *mi)
130 {
131 	kfree(mi->metaval);
132 }
133 EXPORT_SYMBOL_GPL(ife_release_meta_gen);
134 
135 int ife_validate_meta_u32(void *val, int len)
136 {
137 	if (len == 4)
138 		return 0;
139 
140 	return -EINVAL;
141 }
142 EXPORT_SYMBOL_GPL(ife_validate_meta_u32);
143 
144 int ife_validate_meta_u16(void *val, int len)
145 {
146 	/* length will include padding */
147 	if (len == NLA_ALIGN(2))
148 		return 0;
149 
150 	return -EINVAL;
151 }
152 EXPORT_SYMBOL_GPL(ife_validate_meta_u16);
153 
154 static LIST_HEAD(ifeoplist);
155 static DEFINE_RWLOCK(ife_mod_lock);
156 
157 static struct tcf_meta_ops *find_ife_oplist(u16 metaid)
158 {
159 	struct tcf_meta_ops *o;
160 
161 	read_lock(&ife_mod_lock);
162 	list_for_each_entry(o, &ifeoplist, list) {
163 		if (o->metaid == metaid) {
164 			if (!try_module_get(o->owner))
165 				o = NULL;
166 			read_unlock(&ife_mod_lock);
167 			return o;
168 		}
169 	}
170 	read_unlock(&ife_mod_lock);
171 
172 	return NULL;
173 }
174 
175 int register_ife_op(struct tcf_meta_ops *mops)
176 {
177 	struct tcf_meta_ops *m;
178 
179 	if (!mops->metaid || !mops->metatype || !mops->name ||
180 	    !mops->check_presence || !mops->encode || !mops->decode ||
181 	    !mops->get || !mops->alloc)
182 		return -EINVAL;
183 
184 	write_lock(&ife_mod_lock);
185 
186 	list_for_each_entry(m, &ifeoplist, list) {
187 		if (m->metaid == mops->metaid ||
188 		    (strcmp(mops->name, m->name) == 0)) {
189 			write_unlock(&ife_mod_lock);
190 			return -EEXIST;
191 		}
192 	}
193 
194 	if (!mops->release)
195 		mops->release = ife_release_meta_gen;
196 
197 	list_add_tail(&mops->list, &ifeoplist);
198 	write_unlock(&ife_mod_lock);
199 	return 0;
200 }
201 EXPORT_SYMBOL_GPL(unregister_ife_op);
202 
203 int unregister_ife_op(struct tcf_meta_ops *mops)
204 {
205 	struct tcf_meta_ops *m;
206 	int err = -ENOENT;
207 
208 	write_lock(&ife_mod_lock);
209 	list_for_each_entry(m, &ifeoplist, list) {
210 		if (m->metaid == mops->metaid) {
211 			list_del(&mops->list);
212 			err = 0;
213 			break;
214 		}
215 	}
216 	write_unlock(&ife_mod_lock);
217 
218 	return err;
219 }
220 EXPORT_SYMBOL_GPL(register_ife_op);
221 
222 static int ife_validate_metatype(struct tcf_meta_ops *ops, void *val, int len)
223 {
224 	int ret = 0;
225 	/* XXX: unfortunately cant use nla_policy at this point
226 	* because a length of 0 is valid in the case of
227 	* "allow". "use" semantics do enforce for proper
228 	* length and i couldve use nla_policy but it makes it hard
229 	* to use it just for that..
230 	*/
231 	if (ops->validate)
232 		return ops->validate(val, len);
233 
234 	if (ops->metatype == NLA_U32)
235 		ret = ife_validate_meta_u32(val, len);
236 	else if (ops->metatype == NLA_U16)
237 		ret = ife_validate_meta_u16(val, len);
238 
239 	return ret;
240 }
241 
242 /* called when adding new meta information
243  * under ife->tcf_lock
244 */
245 static int load_metaops_and_vet(struct tcf_ife_info *ife, u32 metaid,
246 				void *val, int len)
247 {
248 	struct tcf_meta_ops *ops = find_ife_oplist(metaid);
249 	int ret = 0;
250 
251 	if (!ops) {
252 		ret = -ENOENT;
253 #ifdef CONFIG_MODULES
254 		spin_unlock_bh(&ife->tcf_lock);
255 		rtnl_unlock();
256 		request_module("ifemeta%u", metaid);
257 		rtnl_lock();
258 		spin_lock_bh(&ife->tcf_lock);
259 		ops = find_ife_oplist(metaid);
260 #endif
261 	}
262 
263 	if (ops) {
264 		ret = 0;
265 		if (len)
266 			ret = ife_validate_metatype(ops, val, len);
267 
268 		module_put(ops->owner);
269 	}
270 
271 	return ret;
272 }
273 
274 /* called when adding new meta information
275  * under ife->tcf_lock
276 */
277 static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval,
278 			int len)
279 {
280 	struct tcf_meta_info *mi = NULL;
281 	struct tcf_meta_ops *ops = find_ife_oplist(metaid);
282 	int ret = 0;
283 
284 	if (!ops)
285 		return -ENOENT;
286 
287 	mi = kzalloc(sizeof(*mi), GFP_KERNEL);
288 	if (!mi) {
289 		/*put back what find_ife_oplist took */
290 		module_put(ops->owner);
291 		return -ENOMEM;
292 	}
293 
294 	mi->metaid = metaid;
295 	mi->ops = ops;
296 	if (len > 0) {
297 		ret = ops->alloc(mi, metaval);
298 		if (ret != 0) {
299 			kfree(mi);
300 			module_put(ops->owner);
301 			return ret;
302 		}
303 	}
304 
305 	list_add_tail(&mi->metalist, &ife->metalist);
306 
307 	return ret;
308 }
309 
310 static int use_all_metadata(struct tcf_ife_info *ife)
311 {
312 	struct tcf_meta_ops *o;
313 	int rc = 0;
314 	int installed = 0;
315 
316 	list_for_each_entry(o, &ifeoplist, list) {
317 		rc = add_metainfo(ife, o->metaid, NULL, 0);
318 		if (rc == 0)
319 			installed += 1;
320 	}
321 
322 	if (installed)
323 		return 0;
324 	else
325 		return -EINVAL;
326 }
327 
328 static int dump_metalist(struct sk_buff *skb, struct tcf_ife_info *ife)
329 {
330 	struct tcf_meta_info *e;
331 	struct nlattr *nest;
332 	unsigned char *b = skb_tail_pointer(skb);
333 	int total_encoded = 0;
334 
335 	/*can only happen on decode */
336 	if (list_empty(&ife->metalist))
337 		return 0;
338 
339 	nest = nla_nest_start(skb, TCA_IFE_METALST);
340 	if (!nest)
341 		goto out_nlmsg_trim;
342 
343 	list_for_each_entry(e, &ife->metalist, metalist) {
344 		if (!e->ops->get(skb, e))
345 			total_encoded += 1;
346 	}
347 
348 	if (!total_encoded)
349 		goto out_nlmsg_trim;
350 
351 	nla_nest_end(skb, nest);
352 
353 	return 0;
354 
355 out_nlmsg_trim:
356 	nlmsg_trim(skb, b);
357 	return -1;
358 }
359 
360 /* under ife->tcf_lock */
361 static void _tcf_ife_cleanup(struct tc_action *a, int bind)
362 {
363 	struct tcf_ife_info *ife = a->priv;
364 	struct tcf_meta_info *e, *n;
365 
366 	list_for_each_entry_safe(e, n, &ife->metalist, metalist) {
367 		module_put(e->ops->owner);
368 		list_del(&e->metalist);
369 		if (e->metaval) {
370 			if (e->ops->release)
371 				e->ops->release(e);
372 			else
373 				kfree(e->metaval);
374 		}
375 		kfree(e);
376 	}
377 }
378 
379 static void tcf_ife_cleanup(struct tc_action *a, int bind)
380 {
381 	struct tcf_ife_info *ife = a->priv;
382 
383 	spin_lock_bh(&ife->tcf_lock);
384 	_tcf_ife_cleanup(a, bind);
385 	spin_unlock_bh(&ife->tcf_lock);
386 }
387 
388 /* under ife->tcf_lock */
389 static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb)
390 {
391 	int len = 0;
392 	int rc = 0;
393 	int i = 0;
394 	void *val;
395 
396 	for (i = 1; i < max_metacnt; i++) {
397 		if (tb[i]) {
398 			val = nla_data(tb[i]);
399 			len = nla_len(tb[i]);
400 
401 			rc = load_metaops_and_vet(ife, i, val, len);
402 			if (rc != 0)
403 				return rc;
404 
405 			rc = add_metainfo(ife, i, val, len);
406 			if (rc)
407 				return rc;
408 		}
409 	}
410 
411 	return rc;
412 }
413 
414 static int tcf_ife_init(struct net *net, struct nlattr *nla,
415 			struct nlattr *est, struct tc_action *a,
416 			int ovr, int bind)
417 {
418 	struct tc_action_net *tn = net_generic(net, ife_net_id);
419 	struct nlattr *tb[TCA_IFE_MAX + 1];
420 	struct nlattr *tb2[IFE_META_MAX + 1];
421 	struct tcf_ife_info *ife;
422 	struct tc_ife *parm;
423 	u16 ife_type = 0;
424 	u8 *daddr = NULL;
425 	u8 *saddr = NULL;
426 	int ret = 0, exists = 0;
427 	int err;
428 
429 	err = nla_parse_nested(tb, TCA_IFE_MAX, nla, ife_policy);
430 	if (err < 0)
431 		return err;
432 
433 	if (!tb[TCA_IFE_PARMS])
434 		return -EINVAL;
435 
436 	parm = nla_data(tb[TCA_IFE_PARMS]);
437 
438 	exists = tcf_hash_check(tn, parm->index, a, bind);
439 	if (exists && bind)
440 		return 0;
441 
442 	if (parm->flags & IFE_ENCODE) {
443 		/* Until we get issued the ethertype, we cant have
444 		 * a default..
445 		**/
446 		if (!tb[TCA_IFE_TYPE]) {
447 			if (exists)
448 				tcf_hash_release(a, bind);
449 			pr_info("You MUST pass etherype for encoding\n");
450 			return -EINVAL;
451 		}
452 	}
453 
454 	if (!exists) {
455 		ret = tcf_hash_create(tn, parm->index, est, a, sizeof(*ife),
456 				      bind, false);
457 		if (ret)
458 			return ret;
459 		ret = ACT_P_CREATED;
460 	} else {
461 		tcf_hash_release(a, bind);
462 		if (!ovr)
463 			return -EEXIST;
464 	}
465 
466 	ife = to_ife(a);
467 	ife->flags = parm->flags;
468 
469 	if (parm->flags & IFE_ENCODE) {
470 		ife_type = nla_get_u16(tb[TCA_IFE_TYPE]);
471 		if (tb[TCA_IFE_DMAC])
472 			daddr = nla_data(tb[TCA_IFE_DMAC]);
473 		if (tb[TCA_IFE_SMAC])
474 			saddr = nla_data(tb[TCA_IFE_SMAC]);
475 	}
476 
477 	spin_lock_bh(&ife->tcf_lock);
478 	ife->tcf_action = parm->action;
479 
480 	if (parm->flags & IFE_ENCODE) {
481 		if (daddr)
482 			ether_addr_copy(ife->eth_dst, daddr);
483 		else
484 			eth_zero_addr(ife->eth_dst);
485 
486 		if (saddr)
487 			ether_addr_copy(ife->eth_src, saddr);
488 		else
489 			eth_zero_addr(ife->eth_src);
490 
491 		ife->eth_type = ife_type;
492 	}
493 
494 	if (ret == ACT_P_CREATED)
495 		INIT_LIST_HEAD(&ife->metalist);
496 
497 	if (tb[TCA_IFE_METALST]) {
498 		err = nla_parse_nested(tb2, IFE_META_MAX, tb[TCA_IFE_METALST],
499 				       NULL);
500 		if (err) {
501 metadata_parse_err:
502 			if (exists)
503 				tcf_hash_release(a, bind);
504 			if (ret == ACT_P_CREATED)
505 				_tcf_ife_cleanup(a, bind);
506 
507 			spin_unlock_bh(&ife->tcf_lock);
508 			return err;
509 		}
510 
511 		err = populate_metalist(ife, tb2);
512 		if (err)
513 			goto metadata_parse_err;
514 
515 	} else {
516 		/* if no passed metadata allow list or passed allow-all
517 		 * then here we process by adding as many supported metadatum
518 		 * as we can. You better have at least one else we are
519 		 * going to bail out
520 		 */
521 		err = use_all_metadata(ife);
522 		if (err) {
523 			if (ret == ACT_P_CREATED)
524 				_tcf_ife_cleanup(a, bind);
525 
526 			spin_unlock_bh(&ife->tcf_lock);
527 			return err;
528 		}
529 	}
530 
531 	spin_unlock_bh(&ife->tcf_lock);
532 
533 	if (ret == ACT_P_CREATED)
534 		tcf_hash_insert(tn, a);
535 
536 	return ret;
537 }
538 
539 static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind,
540 			int ref)
541 {
542 	unsigned char *b = skb_tail_pointer(skb);
543 	struct tcf_ife_info *ife = a->priv;
544 	struct tc_ife opt = {
545 		.index = ife->tcf_index,
546 		.refcnt = ife->tcf_refcnt - ref,
547 		.bindcnt = ife->tcf_bindcnt - bind,
548 		.action = ife->tcf_action,
549 		.flags = ife->flags,
550 	};
551 	struct tcf_t t;
552 
553 	if (nla_put(skb, TCA_IFE_PARMS, sizeof(opt), &opt))
554 		goto nla_put_failure;
555 
556 	t.install = jiffies_to_clock_t(jiffies - ife->tcf_tm.install);
557 	t.lastuse = jiffies_to_clock_t(jiffies - ife->tcf_tm.lastuse);
558 	t.expires = jiffies_to_clock_t(ife->tcf_tm.expires);
559 	if (nla_put_64bit(skb, TCA_IFE_TM, sizeof(t), &t, TCA_IFE_PAD))
560 		goto nla_put_failure;
561 
562 	if (!is_zero_ether_addr(ife->eth_dst)) {
563 		if (nla_put(skb, TCA_IFE_DMAC, ETH_ALEN, ife->eth_dst))
564 			goto nla_put_failure;
565 	}
566 
567 	if (!is_zero_ether_addr(ife->eth_src)) {
568 		if (nla_put(skb, TCA_IFE_SMAC, ETH_ALEN, ife->eth_src))
569 			goto nla_put_failure;
570 	}
571 
572 	if (nla_put(skb, TCA_IFE_TYPE, 2, &ife->eth_type))
573 		goto nla_put_failure;
574 
575 	if (dump_metalist(skb, ife)) {
576 		/*ignore failure to dump metalist */
577 		pr_info("Failed to dump metalist\n");
578 	}
579 
580 	return skb->len;
581 
582 nla_put_failure:
583 	nlmsg_trim(skb, b);
584 	return -1;
585 }
586 
587 int find_decode_metaid(struct sk_buff *skb, struct tcf_ife_info *ife,
588 		       u16 metaid, u16 mlen, void *mdata)
589 {
590 	struct tcf_meta_info *e;
591 
592 	/* XXX: use hash to speed up */
593 	list_for_each_entry(e, &ife->metalist, metalist) {
594 		if (metaid == e->metaid) {
595 			if (e->ops) {
596 				/* We check for decode presence already */
597 				return e->ops->decode(skb, mdata, mlen);
598 			}
599 		}
600 	}
601 
602 	return 0;
603 }
604 
605 struct ifeheadr {
606 	__be16 metalen;
607 	u8 tlv_data[];
608 };
609 
610 struct meta_tlvhdr {
611 	__be16 type;
612 	__be16 len;
613 };
614 
615 static int tcf_ife_decode(struct sk_buff *skb, const struct tc_action *a,
616 			  struct tcf_result *res)
617 {
618 	struct tcf_ife_info *ife = a->priv;
619 	int action = ife->tcf_action;
620 	struct ifeheadr *ifehdr = (struct ifeheadr *)skb->data;
621 	u16 ifehdrln = ifehdr->metalen;
622 	struct meta_tlvhdr *tlv = (struct meta_tlvhdr *)(ifehdr->tlv_data);
623 
624 	spin_lock(&ife->tcf_lock);
625 	bstats_update(&ife->tcf_bstats, skb);
626 	ife->tcf_tm.lastuse = jiffies;
627 	spin_unlock(&ife->tcf_lock);
628 
629 	ifehdrln = ntohs(ifehdrln);
630 	if (unlikely(!pskb_may_pull(skb, ifehdrln))) {
631 		spin_lock(&ife->tcf_lock);
632 		ife->tcf_qstats.drops++;
633 		spin_unlock(&ife->tcf_lock);
634 		return TC_ACT_SHOT;
635 	}
636 
637 	skb_set_mac_header(skb, ifehdrln);
638 	__skb_pull(skb, ifehdrln);
639 	skb->protocol = eth_type_trans(skb, skb->dev);
640 	ifehdrln -= IFE_METAHDRLEN;
641 
642 	while (ifehdrln > 0) {
643 		u8 *tlvdata = (u8 *)tlv;
644 		u16 mtype = tlv->type;
645 		u16 mlen = tlv->len;
646 
647 		mtype = ntohs(mtype);
648 		mlen = ntohs(mlen);
649 
650 		if (find_decode_metaid(skb, ife, mtype, (mlen - 4),
651 				       (void *)(tlvdata + 4))) {
652 			/* abuse overlimits to count when we receive metadata
653 			 * but dont have an ops for it
654 			 */
655 			pr_info_ratelimited("Unknown metaid %d alnlen %d\n",
656 					    mtype, mlen);
657 			ife->tcf_qstats.overlimits++;
658 		}
659 
660 		tlvdata += mlen;
661 		ifehdrln -= mlen;
662 		tlv = (struct meta_tlvhdr *)tlvdata;
663 	}
664 
665 	skb_reset_network_header(skb);
666 	return action;
667 }
668 
669 /*XXX: check if we can do this at install time instead of current
670  * send data path
671 **/
672 static int ife_get_sz(struct sk_buff *skb, struct tcf_ife_info *ife)
673 {
674 	struct tcf_meta_info *e, *n;
675 	int tot_run_sz = 0, run_sz = 0;
676 
677 	list_for_each_entry_safe(e, n, &ife->metalist, metalist) {
678 		if (e->ops->check_presence) {
679 			run_sz = e->ops->check_presence(skb, e);
680 			tot_run_sz += run_sz;
681 		}
682 	}
683 
684 	return tot_run_sz;
685 }
686 
687 static int tcf_ife_encode(struct sk_buff *skb, const struct tc_action *a,
688 			  struct tcf_result *res)
689 {
690 	struct tcf_ife_info *ife = a->priv;
691 	int action = ife->tcf_action;
692 	struct ethhdr *oethh;	/* outer ether header */
693 	struct ethhdr *iethh;	/* inner eth header */
694 	struct tcf_meta_info *e;
695 	/*
696 	   OUTERHDR:TOTMETALEN:{TLVHDR:Metadatum:TLVHDR..}:ORIGDATA
697 	   where ORIGDATA = original ethernet header ...
698 	 */
699 	u16 metalen = ife_get_sz(skb, ife);
700 	int hdrm = metalen + skb->dev->hard_header_len + IFE_METAHDRLEN;
701 	unsigned int skboff = skb->dev->hard_header_len;
702 	u32 at = G_TC_AT(skb->tc_verd);
703 	int new_len = skb->len + hdrm;
704 	bool exceed_mtu = false;
705 	int err;
706 
707 	if (at & AT_EGRESS) {
708 		if (new_len > skb->dev->mtu)
709 			exceed_mtu = true;
710 	}
711 
712 	spin_lock(&ife->tcf_lock);
713 	bstats_update(&ife->tcf_bstats, skb);
714 	ife->tcf_tm.lastuse = jiffies;
715 
716 	if (!metalen) {		/* no metadata to send */
717 		/* abuse overlimits to count when we allow packet
718 		 * with no metadata
719 		 */
720 		ife->tcf_qstats.overlimits++;
721 		spin_unlock(&ife->tcf_lock);
722 		return action;
723 	}
724 	/* could be stupid policy setup or mtu config
725 	 * so lets be conservative.. */
726 	if ((action == TC_ACT_SHOT) || exceed_mtu) {
727 		ife->tcf_qstats.drops++;
728 		spin_unlock(&ife->tcf_lock);
729 		return TC_ACT_SHOT;
730 	}
731 
732 	iethh = eth_hdr(skb);
733 
734 	err = skb_cow_head(skb, hdrm);
735 	if (unlikely(err)) {
736 		ife->tcf_qstats.drops++;
737 		spin_unlock(&ife->tcf_lock);
738 		return TC_ACT_SHOT;
739 	}
740 
741 	if (!(at & AT_EGRESS))
742 		skb_push(skb, skb->dev->hard_header_len);
743 
744 	__skb_push(skb, hdrm);
745 	memcpy(skb->data, iethh, skb->mac_len);
746 	skb_reset_mac_header(skb);
747 	oethh = eth_hdr(skb);
748 
749 	/*total metadata length */
750 	metalen += IFE_METAHDRLEN;
751 	metalen = htons(metalen);
752 	memcpy((skb->data + skboff), &metalen, IFE_METAHDRLEN);
753 	skboff += IFE_METAHDRLEN;
754 
755 	/* XXX: we dont have a clever way of telling encode to
756 	 * not repeat some of the computations that are done by
757 	 * ops->presence_check...
758 	 */
759 	list_for_each_entry(e, &ife->metalist, metalist) {
760 		if (e->ops->encode) {
761 			err = e->ops->encode(skb, (void *)(skb->data + skboff),
762 					     e);
763 		}
764 		if (err < 0) {
765 			/* too corrupt to keep around if overwritten */
766 			ife->tcf_qstats.drops++;
767 			spin_unlock(&ife->tcf_lock);
768 			return TC_ACT_SHOT;
769 		}
770 		skboff += err;
771 	}
772 
773 	if (!is_zero_ether_addr(ife->eth_src))
774 		ether_addr_copy(oethh->h_source, ife->eth_src);
775 	else
776 		ether_addr_copy(oethh->h_source, iethh->h_source);
777 	if (!is_zero_ether_addr(ife->eth_dst))
778 		ether_addr_copy(oethh->h_dest, ife->eth_dst);
779 	else
780 		ether_addr_copy(oethh->h_dest, iethh->h_dest);
781 	oethh->h_proto = htons(ife->eth_type);
782 
783 	if (!(at & AT_EGRESS))
784 		skb_pull(skb, skb->dev->hard_header_len);
785 
786 	spin_unlock(&ife->tcf_lock);
787 
788 	return action;
789 }
790 
791 static int tcf_ife_act(struct sk_buff *skb, const struct tc_action *a,
792 		       struct tcf_result *res)
793 {
794 	struct tcf_ife_info *ife = a->priv;
795 
796 	if (ife->flags & IFE_ENCODE)
797 		return tcf_ife_encode(skb, a, res);
798 
799 	if (!(ife->flags & IFE_ENCODE))
800 		return tcf_ife_decode(skb, a, res);
801 
802 	pr_info_ratelimited("unknown failure(policy neither de/encode\n");
803 	spin_lock(&ife->tcf_lock);
804 	bstats_update(&ife->tcf_bstats, skb);
805 	ife->tcf_tm.lastuse = jiffies;
806 	ife->tcf_qstats.drops++;
807 	spin_unlock(&ife->tcf_lock);
808 
809 	return TC_ACT_SHOT;
810 }
811 
812 static int tcf_ife_walker(struct net *net, struct sk_buff *skb,
813 			  struct netlink_callback *cb, int type,
814 			  struct tc_action *a)
815 {
816 	struct tc_action_net *tn = net_generic(net, ife_net_id);
817 
818 	return tcf_generic_walker(tn, skb, cb, type, a);
819 }
820 
821 static int tcf_ife_search(struct net *net, struct tc_action *a, u32 index)
822 {
823 	struct tc_action_net *tn = net_generic(net, ife_net_id);
824 
825 	return tcf_hash_search(tn, a, index);
826 }
827 
828 static struct tc_action_ops act_ife_ops = {
829 	.kind = "ife",
830 	.type = TCA_ACT_IFE,
831 	.owner = THIS_MODULE,
832 	.act = tcf_ife_act,
833 	.dump = tcf_ife_dump,
834 	.cleanup = tcf_ife_cleanup,
835 	.init = tcf_ife_init,
836 	.walk = tcf_ife_walker,
837 	.lookup = tcf_ife_search,
838 };
839 
840 static __net_init int ife_init_net(struct net *net)
841 {
842 	struct tc_action_net *tn = net_generic(net, ife_net_id);
843 
844 	return tc_action_net_init(tn, &act_ife_ops, IFE_TAB_MASK);
845 }
846 
847 static void __net_exit ife_exit_net(struct net *net)
848 {
849 	struct tc_action_net *tn = net_generic(net, ife_net_id);
850 
851 	tc_action_net_exit(tn);
852 }
853 
854 static struct pernet_operations ife_net_ops = {
855 	.init = ife_init_net,
856 	.exit = ife_exit_net,
857 	.id   = &ife_net_id,
858 	.size = sizeof(struct tc_action_net),
859 };
860 
861 static int __init ife_init_module(void)
862 {
863 	return tcf_register_action(&act_ife_ops, &ife_net_ops);
864 }
865 
866 static void __exit ife_cleanup_module(void)
867 {
868 	tcf_unregister_action(&act_ife_ops, &ife_net_ops);
869 }
870 
871 module_init(ife_init_module);
872 module_exit(ife_cleanup_module);
873 
874 MODULE_AUTHOR("Jamal Hadi Salim(2015)");
875 MODULE_DESCRIPTION("Inter-FE LFB action");
876 MODULE_LICENSE("GPL");
877