xref: /openbmc/linux/net/sched/act_csum.c (revision 3c8c1539)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Checksum updating actions
4  *
5  * Copyright (c) 2010 Gregoire Baron <baronchon@n7mm.org>
6  */
7 
8 #include <linux/types.h>
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/spinlock.h>
13 
14 #include <linux/netlink.h>
15 #include <net/netlink.h>
16 #include <linux/rtnetlink.h>
17 
18 #include <linux/skbuff.h>
19 
20 #include <net/ip.h>
21 #include <net/ipv6.h>
22 #include <net/icmp.h>
23 #include <linux/icmpv6.h>
24 #include <linux/igmp.h>
25 #include <net/tcp.h>
26 #include <net/udp.h>
27 #include <net/ip6_checksum.h>
28 #include <net/sctp/checksum.h>
29 
30 #include <net/act_api.h>
31 #include <net/pkt_cls.h>
32 
33 #include <linux/tc_act/tc_csum.h>
34 #include <net/tc_act/tc_csum.h>
35 
36 static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
37 	[TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
38 };
39 
40 static unsigned int csum_net_id;
41 static struct tc_action_ops act_csum_ops;
42 
43 static int tcf_csum_init(struct net *net, struct nlattr *nla,
44 			 struct nlattr *est, struct tc_action **a,
45 			 struct tcf_proto *tp,
46 			 u32 flags, struct netlink_ext_ack *extack)
47 {
48 	struct tc_action_net *tn = net_generic(net, csum_net_id);
49 	bool bind = flags & TCA_ACT_FLAGS_BIND;
50 	struct tcf_csum_params *params_new;
51 	struct nlattr *tb[TCA_CSUM_MAX + 1];
52 	struct tcf_chain *goto_ch = NULL;
53 	struct tc_csum *parm;
54 	struct tcf_csum *p;
55 	int ret = 0, err;
56 	u32 index;
57 
58 	if (nla == NULL)
59 		return -EINVAL;
60 
61 	err = nla_parse_nested_deprecated(tb, TCA_CSUM_MAX, nla, csum_policy,
62 					  NULL);
63 	if (err < 0)
64 		return err;
65 
66 	if (tb[TCA_CSUM_PARMS] == NULL)
67 		return -EINVAL;
68 	parm = nla_data(tb[TCA_CSUM_PARMS]);
69 	index = parm->index;
70 	err = tcf_idr_check_alloc(tn, &index, a, bind);
71 	if (!err) {
72 		ret = tcf_idr_create_from_flags(tn, index, est, a,
73 						&act_csum_ops, bind, flags);
74 		if (ret) {
75 			tcf_idr_cleanup(tn, index);
76 			return ret;
77 		}
78 		ret = ACT_P_CREATED;
79 	} else if (err > 0) {
80 		if (bind)/* dont override defaults */
81 			return 0;
82 		if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
83 			tcf_idr_release(*a, bind);
84 			return -EEXIST;
85 		}
86 	} else {
87 		return err;
88 	}
89 
90 	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
91 	if (err < 0)
92 		goto release_idr;
93 
94 	p = to_tcf_csum(*a);
95 
96 	params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
97 	if (unlikely(!params_new)) {
98 		err = -ENOMEM;
99 		goto put_chain;
100 	}
101 	params_new->update_flags = parm->update_flags;
102 
103 	spin_lock_bh(&p->tcf_lock);
104 	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
105 	params_new = rcu_replace_pointer(p->params, params_new,
106 					 lockdep_is_held(&p->tcf_lock));
107 	spin_unlock_bh(&p->tcf_lock);
108 
109 	if (goto_ch)
110 		tcf_chain_put_by_act(goto_ch);
111 	if (params_new)
112 		kfree_rcu(params_new, rcu);
113 
114 	return ret;
115 put_chain:
116 	if (goto_ch)
117 		tcf_chain_put_by_act(goto_ch);
118 release_idr:
119 	tcf_idr_release(*a, bind);
120 	return err;
121 }
122 
123 /**
124  * tcf_csum_skb_nextlayer - Get next layer pointer
125  * @skb: sk_buff to use
126  * @ihl: previous summed headers length
127  * @ipl: complete packet length
128  * @jhl: next header length
129  *
130  * Check the expected next layer availability in the specified sk_buff.
131  * Return the next layer pointer if pass, NULL otherwise.
132  */
133 static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
134 				    unsigned int ihl, unsigned int ipl,
135 				    unsigned int jhl)
136 {
137 	int ntkoff = skb_network_offset(skb);
138 	int hl = ihl + jhl;
139 
140 	if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
141 	    skb_try_make_writable(skb, hl + ntkoff))
142 		return NULL;
143 	else
144 		return (void *)(skb_network_header(skb) + ihl);
145 }
146 
147 static int tcf_csum_ipv4_icmp(struct sk_buff *skb, unsigned int ihl,
148 			      unsigned int ipl)
149 {
150 	struct icmphdr *icmph;
151 
152 	icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
153 	if (icmph == NULL)
154 		return 0;
155 
156 	icmph->checksum = 0;
157 	skb->csum = csum_partial(icmph, ipl - ihl, 0);
158 	icmph->checksum = csum_fold(skb->csum);
159 
160 	skb->ip_summed = CHECKSUM_NONE;
161 
162 	return 1;
163 }
164 
165 static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
166 			      unsigned int ihl, unsigned int ipl)
167 {
168 	struct igmphdr *igmph;
169 
170 	igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
171 	if (igmph == NULL)
172 		return 0;
173 
174 	igmph->csum = 0;
175 	skb->csum = csum_partial(igmph, ipl - ihl, 0);
176 	igmph->csum = csum_fold(skb->csum);
177 
178 	skb->ip_summed = CHECKSUM_NONE;
179 
180 	return 1;
181 }
182 
183 static int tcf_csum_ipv6_icmp(struct sk_buff *skb, unsigned int ihl,
184 			      unsigned int ipl)
185 {
186 	struct icmp6hdr *icmp6h;
187 	const struct ipv6hdr *ip6h;
188 
189 	icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
190 	if (icmp6h == NULL)
191 		return 0;
192 
193 	ip6h = ipv6_hdr(skb);
194 	icmp6h->icmp6_cksum = 0;
195 	skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
196 	icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
197 					      ipl - ihl, IPPROTO_ICMPV6,
198 					      skb->csum);
199 
200 	skb->ip_summed = CHECKSUM_NONE;
201 
202 	return 1;
203 }
204 
205 static int tcf_csum_ipv4_tcp(struct sk_buff *skb, unsigned int ihl,
206 			     unsigned int ipl)
207 {
208 	struct tcphdr *tcph;
209 	const struct iphdr *iph;
210 
211 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
212 		return 1;
213 
214 	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
215 	if (tcph == NULL)
216 		return 0;
217 
218 	iph = ip_hdr(skb);
219 	tcph->check = 0;
220 	skb->csum = csum_partial(tcph, ipl - ihl, 0);
221 	tcph->check = tcp_v4_check(ipl - ihl,
222 				   iph->saddr, iph->daddr, skb->csum);
223 
224 	skb->ip_summed = CHECKSUM_NONE;
225 
226 	return 1;
227 }
228 
229 static int tcf_csum_ipv6_tcp(struct sk_buff *skb, unsigned int ihl,
230 			     unsigned int ipl)
231 {
232 	struct tcphdr *tcph;
233 	const struct ipv6hdr *ip6h;
234 
235 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
236 		return 1;
237 
238 	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
239 	if (tcph == NULL)
240 		return 0;
241 
242 	ip6h = ipv6_hdr(skb);
243 	tcph->check = 0;
244 	skb->csum = csum_partial(tcph, ipl - ihl, 0);
245 	tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
246 				      ipl - ihl, IPPROTO_TCP,
247 				      skb->csum);
248 
249 	skb->ip_summed = CHECKSUM_NONE;
250 
251 	return 1;
252 }
253 
254 static int tcf_csum_ipv4_udp(struct sk_buff *skb, unsigned int ihl,
255 			     unsigned int ipl, int udplite)
256 {
257 	struct udphdr *udph;
258 	const struct iphdr *iph;
259 	u16 ul;
260 
261 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
262 		return 1;
263 
264 	/*
265 	 * Support both UDP and UDPLITE checksum algorithms, Don't use
266 	 * udph->len to get the real length without any protocol check,
267 	 * UDPLITE uses udph->len for another thing,
268 	 * Use iph->tot_len, or just ipl.
269 	 */
270 
271 	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
272 	if (udph == NULL)
273 		return 0;
274 
275 	iph = ip_hdr(skb);
276 	ul = ntohs(udph->len);
277 
278 	if (udplite || udph->check) {
279 
280 		udph->check = 0;
281 
282 		if (udplite) {
283 			if (ul == 0)
284 				skb->csum = csum_partial(udph, ipl - ihl, 0);
285 			else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
286 				skb->csum = csum_partial(udph, ul, 0);
287 			else
288 				goto ignore_obscure_skb;
289 		} else {
290 			if (ul != ipl - ihl)
291 				goto ignore_obscure_skb;
292 
293 			skb->csum = csum_partial(udph, ul, 0);
294 		}
295 
296 		udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
297 						ul, iph->protocol,
298 						skb->csum);
299 
300 		if (!udph->check)
301 			udph->check = CSUM_MANGLED_0;
302 	}
303 
304 	skb->ip_summed = CHECKSUM_NONE;
305 
306 ignore_obscure_skb:
307 	return 1;
308 }
309 
310 static int tcf_csum_ipv6_udp(struct sk_buff *skb, unsigned int ihl,
311 			     unsigned int ipl, int udplite)
312 {
313 	struct udphdr *udph;
314 	const struct ipv6hdr *ip6h;
315 	u16 ul;
316 
317 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
318 		return 1;
319 
320 	/*
321 	 * Support both UDP and UDPLITE checksum algorithms, Don't use
322 	 * udph->len to get the real length without any protocol check,
323 	 * UDPLITE uses udph->len for another thing,
324 	 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
325 	 */
326 
327 	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
328 	if (udph == NULL)
329 		return 0;
330 
331 	ip6h = ipv6_hdr(skb);
332 	ul = ntohs(udph->len);
333 
334 	udph->check = 0;
335 
336 	if (udplite) {
337 		if (ul == 0)
338 			skb->csum = csum_partial(udph, ipl - ihl, 0);
339 
340 		else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
341 			skb->csum = csum_partial(udph, ul, 0);
342 
343 		else
344 			goto ignore_obscure_skb;
345 	} else {
346 		if (ul != ipl - ihl)
347 			goto ignore_obscure_skb;
348 
349 		skb->csum = csum_partial(udph, ul, 0);
350 	}
351 
352 	udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
353 				      udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
354 				      skb->csum);
355 
356 	if (!udph->check)
357 		udph->check = CSUM_MANGLED_0;
358 
359 	skb->ip_summed = CHECKSUM_NONE;
360 
361 ignore_obscure_skb:
362 	return 1;
363 }
364 
365 static int tcf_csum_sctp(struct sk_buff *skb, unsigned int ihl,
366 			 unsigned int ipl)
367 {
368 	struct sctphdr *sctph;
369 
370 	if (skb_is_gso(skb) && skb_is_gso_sctp(skb))
371 		return 1;
372 
373 	sctph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*sctph));
374 	if (!sctph)
375 		return 0;
376 
377 	sctph->checksum = sctp_compute_cksum(skb,
378 					     skb_network_offset(skb) + ihl);
379 	skb->ip_summed = CHECKSUM_NONE;
380 	skb->csum_not_inet = 0;
381 
382 	return 1;
383 }
384 
385 static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
386 {
387 	const struct iphdr *iph;
388 	int ntkoff;
389 
390 	ntkoff = skb_network_offset(skb);
391 
392 	if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
393 		goto fail;
394 
395 	iph = ip_hdr(skb);
396 
397 	switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
398 	case IPPROTO_ICMP:
399 		if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
400 			if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
401 						ntohs(iph->tot_len)))
402 				goto fail;
403 		break;
404 	case IPPROTO_IGMP:
405 		if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
406 			if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
407 						ntohs(iph->tot_len)))
408 				goto fail;
409 		break;
410 	case IPPROTO_TCP:
411 		if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
412 			if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
413 					       ntohs(iph->tot_len)))
414 				goto fail;
415 		break;
416 	case IPPROTO_UDP:
417 		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
418 			if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
419 					       ntohs(iph->tot_len), 0))
420 				goto fail;
421 		break;
422 	case IPPROTO_UDPLITE:
423 		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
424 			if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
425 					       ntohs(iph->tot_len), 1))
426 				goto fail;
427 		break;
428 	case IPPROTO_SCTP:
429 		if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
430 		    !tcf_csum_sctp(skb, iph->ihl * 4, ntohs(iph->tot_len)))
431 			goto fail;
432 		break;
433 	}
434 
435 	if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
436 		if (skb_try_make_writable(skb, sizeof(*iph) + ntkoff))
437 			goto fail;
438 
439 		ip_send_check(ip_hdr(skb));
440 	}
441 
442 	return 1;
443 
444 fail:
445 	return 0;
446 }
447 
448 static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh, unsigned int ixhl,
449 				 unsigned int *pl)
450 {
451 	int off, len, optlen;
452 	unsigned char *xh = (void *)ip6xh;
453 
454 	off = sizeof(*ip6xh);
455 	len = ixhl - off;
456 
457 	while (len > 1) {
458 		switch (xh[off]) {
459 		case IPV6_TLV_PAD1:
460 			optlen = 1;
461 			break;
462 		case IPV6_TLV_JUMBO:
463 			optlen = xh[off + 1] + 2;
464 			if (optlen != 6 || len < 6 || (off & 3) != 2)
465 				/* wrong jumbo option length/alignment */
466 				return 0;
467 			*pl = ntohl(*(__be32 *)(xh + off + 2));
468 			goto done;
469 		default:
470 			optlen = xh[off + 1] + 2;
471 			if (optlen > len)
472 				/* ignore obscure options */
473 				goto done;
474 			break;
475 		}
476 		off += optlen;
477 		len -= optlen;
478 	}
479 
480 done:
481 	return 1;
482 }
483 
484 static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
485 {
486 	struct ipv6hdr *ip6h;
487 	struct ipv6_opt_hdr *ip6xh;
488 	unsigned int hl, ixhl;
489 	unsigned int pl;
490 	int ntkoff;
491 	u8 nexthdr;
492 
493 	ntkoff = skb_network_offset(skb);
494 
495 	hl = sizeof(*ip6h);
496 
497 	if (!pskb_may_pull(skb, hl + ntkoff))
498 		goto fail;
499 
500 	ip6h = ipv6_hdr(skb);
501 
502 	pl = ntohs(ip6h->payload_len);
503 	nexthdr = ip6h->nexthdr;
504 
505 	do {
506 		switch (nexthdr) {
507 		case NEXTHDR_FRAGMENT:
508 			goto ignore_skb;
509 		case NEXTHDR_ROUTING:
510 		case NEXTHDR_HOP:
511 		case NEXTHDR_DEST:
512 			if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
513 				goto fail;
514 			ip6xh = (void *)(skb_network_header(skb) + hl);
515 			ixhl = ipv6_optlen(ip6xh);
516 			if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
517 				goto fail;
518 			ip6xh = (void *)(skb_network_header(skb) + hl);
519 			if ((nexthdr == NEXTHDR_HOP) &&
520 			    !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
521 				goto fail;
522 			nexthdr = ip6xh->nexthdr;
523 			hl += ixhl;
524 			break;
525 		case IPPROTO_ICMPV6:
526 			if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
527 				if (!tcf_csum_ipv6_icmp(skb,
528 							hl, pl + sizeof(*ip6h)))
529 					goto fail;
530 			goto done;
531 		case IPPROTO_TCP:
532 			if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
533 				if (!tcf_csum_ipv6_tcp(skb,
534 						       hl, pl + sizeof(*ip6h)))
535 					goto fail;
536 			goto done;
537 		case IPPROTO_UDP:
538 			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
539 				if (!tcf_csum_ipv6_udp(skb, hl,
540 						       pl + sizeof(*ip6h), 0))
541 					goto fail;
542 			goto done;
543 		case IPPROTO_UDPLITE:
544 			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
545 				if (!tcf_csum_ipv6_udp(skb, hl,
546 						       pl + sizeof(*ip6h), 1))
547 					goto fail;
548 			goto done;
549 		case IPPROTO_SCTP:
550 			if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
551 			    !tcf_csum_sctp(skb, hl, pl + sizeof(*ip6h)))
552 				goto fail;
553 			goto done;
554 		default:
555 			goto ignore_skb;
556 		}
557 	} while (pskb_may_pull(skb, hl + 1 + ntkoff));
558 
559 done:
560 ignore_skb:
561 	return 1;
562 
563 fail:
564 	return 0;
565 }
566 
567 static int tcf_csum_act(struct sk_buff *skb, const struct tc_action *a,
568 			struct tcf_result *res)
569 {
570 	struct tcf_csum *p = to_tcf_csum(a);
571 	bool orig_vlan_tag_present = false;
572 	unsigned int vlan_hdr_count = 0;
573 	struct tcf_csum_params *params;
574 	u32 update_flags;
575 	__be16 protocol;
576 	int action;
577 
578 	params = rcu_dereference_bh(p->params);
579 
580 	tcf_lastuse_update(&p->tcf_tm);
581 	tcf_action_update_bstats(&p->common, skb);
582 
583 	action = READ_ONCE(p->tcf_action);
584 	if (unlikely(action == TC_ACT_SHOT))
585 		goto drop;
586 
587 	update_flags = params->update_flags;
588 	protocol = skb_protocol(skb, false);
589 again:
590 	switch (protocol) {
591 	case cpu_to_be16(ETH_P_IP):
592 		if (!tcf_csum_ipv4(skb, update_flags))
593 			goto drop;
594 		break;
595 	case cpu_to_be16(ETH_P_IPV6):
596 		if (!tcf_csum_ipv6(skb, update_flags))
597 			goto drop;
598 		break;
599 	case cpu_to_be16(ETH_P_8021AD):
600 		fallthrough;
601 	case cpu_to_be16(ETH_P_8021Q):
602 		if (skb_vlan_tag_present(skb) && !orig_vlan_tag_present) {
603 			protocol = skb->protocol;
604 			orig_vlan_tag_present = true;
605 		} else {
606 			struct vlan_hdr *vlan = (struct vlan_hdr *)skb->data;
607 
608 			protocol = vlan->h_vlan_encapsulated_proto;
609 			skb_pull(skb, VLAN_HLEN);
610 			skb_reset_network_header(skb);
611 			vlan_hdr_count++;
612 		}
613 		goto again;
614 	}
615 
616 out:
617 	/* Restore the skb for the pulled VLAN tags */
618 	while (vlan_hdr_count--) {
619 		skb_push(skb, VLAN_HLEN);
620 		skb_reset_network_header(skb);
621 	}
622 
623 	return action;
624 
625 drop:
626 	tcf_action_inc_drop_qstats(&p->common);
627 	action = TC_ACT_SHOT;
628 	goto out;
629 }
630 
631 static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind,
632 			 int ref)
633 {
634 	unsigned char *b = skb_tail_pointer(skb);
635 	struct tcf_csum *p = to_tcf_csum(a);
636 	struct tcf_csum_params *params;
637 	struct tc_csum opt = {
638 		.index   = p->tcf_index,
639 		.refcnt  = refcount_read(&p->tcf_refcnt) - ref,
640 		.bindcnt = atomic_read(&p->tcf_bindcnt) - bind,
641 	};
642 	struct tcf_t t;
643 
644 	spin_lock_bh(&p->tcf_lock);
645 	params = rcu_dereference_protected(p->params,
646 					   lockdep_is_held(&p->tcf_lock));
647 	opt.action = p->tcf_action;
648 	opt.update_flags = params->update_flags;
649 
650 	if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
651 		goto nla_put_failure;
652 
653 	tcf_tm_dump(&t, &p->tcf_tm);
654 	if (nla_put_64bit(skb, TCA_CSUM_TM, sizeof(t), &t, TCA_CSUM_PAD))
655 		goto nla_put_failure;
656 	spin_unlock_bh(&p->tcf_lock);
657 
658 	return skb->len;
659 
660 nla_put_failure:
661 	spin_unlock_bh(&p->tcf_lock);
662 	nlmsg_trim(skb, b);
663 	return -1;
664 }
665 
666 static void tcf_csum_cleanup(struct tc_action *a)
667 {
668 	struct tcf_csum *p = to_tcf_csum(a);
669 	struct tcf_csum_params *params;
670 
671 	params = rcu_dereference_protected(p->params, 1);
672 	if (params)
673 		kfree_rcu(params, rcu);
674 }
675 
676 static int tcf_csum_walker(struct net *net, struct sk_buff *skb,
677 			   struct netlink_callback *cb, int type,
678 			   const struct tc_action_ops *ops,
679 			   struct netlink_ext_ack *extack)
680 {
681 	struct tc_action_net *tn = net_generic(net, csum_net_id);
682 
683 	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
684 }
685 
686 static int tcf_csum_search(struct net *net, struct tc_action **a, u32 index)
687 {
688 	struct tc_action_net *tn = net_generic(net, csum_net_id);
689 
690 	return tcf_idr_search(tn, a, index);
691 }
692 
693 static size_t tcf_csum_get_fill_size(const struct tc_action *act)
694 {
695 	return nla_total_size(sizeof(struct tc_csum));
696 }
697 
698 static struct tc_action_ops act_csum_ops = {
699 	.kind		= "csum",
700 	.id		= TCA_ID_CSUM,
701 	.owner		= THIS_MODULE,
702 	.act		= tcf_csum_act,
703 	.dump		= tcf_csum_dump,
704 	.init		= tcf_csum_init,
705 	.cleanup	= tcf_csum_cleanup,
706 	.walk		= tcf_csum_walker,
707 	.lookup		= tcf_csum_search,
708 	.get_fill_size  = tcf_csum_get_fill_size,
709 	.size		= sizeof(struct tcf_csum),
710 };
711 
712 static __net_init int csum_init_net(struct net *net)
713 {
714 	struct tc_action_net *tn = net_generic(net, csum_net_id);
715 
716 	return tc_action_net_init(net, tn, &act_csum_ops);
717 }
718 
719 static void __net_exit csum_exit_net(struct list_head *net_list)
720 {
721 	tc_action_net_exit(net_list, csum_net_id);
722 }
723 
724 static struct pernet_operations csum_net_ops = {
725 	.init = csum_init_net,
726 	.exit_batch = csum_exit_net,
727 	.id   = &csum_net_id,
728 	.size = sizeof(struct tc_action_net),
729 };
730 
731 MODULE_DESCRIPTION("Checksum updating actions");
732 MODULE_LICENSE("GPL");
733 
734 static int __init csum_init_module(void)
735 {
736 	return tcf_register_action(&act_csum_ops, &csum_net_ops);
737 }
738 
739 static void __exit csum_cleanup_module(void)
740 {
741 	tcf_unregister_action(&act_csum_ops, &csum_net_ops);
742 }
743 
744 module_init(csum_init_module);
745 module_exit(csum_cleanup_module);
746