xref: /openbmc/linux/net/sched/act_csum.c (revision 7f6964c5)
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, int ovr,
45 			 int bind, bool rtnl_held, struct tcf_proto *tp,
46 			 struct netlink_ext_ack *extack)
47 {
48 	struct tc_action_net *tn = net_generic(net, csum_net_id);
49 	struct tcf_csum_params *params_new;
50 	struct nlattr *tb[TCA_CSUM_MAX + 1];
51 	struct tcf_chain *goto_ch = NULL;
52 	struct tc_csum *parm;
53 	struct tcf_csum *p;
54 	int ret = 0, err;
55 
56 	if (nla == NULL)
57 		return -EINVAL;
58 
59 	err = nla_parse_nested_deprecated(tb, TCA_CSUM_MAX, nla, csum_policy,
60 					  NULL);
61 	if (err < 0)
62 		return err;
63 
64 	if (tb[TCA_CSUM_PARMS] == NULL)
65 		return -EINVAL;
66 	parm = nla_data(tb[TCA_CSUM_PARMS]);
67 
68 	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
69 	if (!err) {
70 		ret = tcf_idr_create(tn, parm->index, est, a,
71 				     &act_csum_ops, bind, true);
72 		if (ret) {
73 			tcf_idr_cleanup(tn, parm->index);
74 			return ret;
75 		}
76 		ret = ACT_P_CREATED;
77 	} else if (err > 0) {
78 		if (bind)/* dont override defaults */
79 			return 0;
80 		if (!ovr) {
81 			tcf_idr_release(*a, bind);
82 			return -EEXIST;
83 		}
84 	} else {
85 		return err;
86 	}
87 
88 	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
89 	if (err < 0)
90 		goto release_idr;
91 
92 	p = to_tcf_csum(*a);
93 
94 	params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
95 	if (unlikely(!params_new)) {
96 		err = -ENOMEM;
97 		goto put_chain;
98 	}
99 	params_new->update_flags = parm->update_flags;
100 
101 	spin_lock_bh(&p->tcf_lock);
102 	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
103 	rcu_swap_protected(p->params, params_new,
104 			   lockdep_is_held(&p->tcf_lock));
105 	spin_unlock_bh(&p->tcf_lock);
106 
107 	if (goto_ch)
108 		tcf_chain_put_by_act(goto_ch);
109 	if (params_new)
110 		kfree_rcu(params_new, rcu);
111 
112 	if (ret == ACT_P_CREATED)
113 		tcf_idr_insert(tn, *a);
114 
115 	return ret;
116 put_chain:
117 	if (goto_ch)
118 		tcf_chain_put_by_act(goto_ch);
119 release_idr:
120 	tcf_idr_release(*a, bind);
121 	return err;
122 }
123 
124 /**
125  * tcf_csum_skb_nextlayer - Get next layer pointer
126  * @skb: sk_buff to use
127  * @ihl: previous summed headers length
128  * @ipl: complete packet length
129  * @jhl: next header length
130  *
131  * Check the expected next layer availability in the specified sk_buff.
132  * Return the next layer pointer if pass, NULL otherwise.
133  */
134 static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
135 				    unsigned int ihl, unsigned int ipl,
136 				    unsigned int jhl)
137 {
138 	int ntkoff = skb_network_offset(skb);
139 	int hl = ihl + jhl;
140 
141 	if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
142 	    skb_try_make_writable(skb, hl + ntkoff))
143 		return NULL;
144 	else
145 		return (void *)(skb_network_header(skb) + ihl);
146 }
147 
148 static int tcf_csum_ipv4_icmp(struct sk_buff *skb, unsigned int ihl,
149 			      unsigned int ipl)
150 {
151 	struct icmphdr *icmph;
152 
153 	icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
154 	if (icmph == NULL)
155 		return 0;
156 
157 	icmph->checksum = 0;
158 	skb->csum = csum_partial(icmph, ipl - ihl, 0);
159 	icmph->checksum = csum_fold(skb->csum);
160 
161 	skb->ip_summed = CHECKSUM_NONE;
162 
163 	return 1;
164 }
165 
166 static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
167 			      unsigned int ihl, unsigned int ipl)
168 {
169 	struct igmphdr *igmph;
170 
171 	igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
172 	if (igmph == NULL)
173 		return 0;
174 
175 	igmph->csum = 0;
176 	skb->csum = csum_partial(igmph, ipl - ihl, 0);
177 	igmph->csum = csum_fold(skb->csum);
178 
179 	skb->ip_summed = CHECKSUM_NONE;
180 
181 	return 1;
182 }
183 
184 static int tcf_csum_ipv6_icmp(struct sk_buff *skb, unsigned int ihl,
185 			      unsigned int ipl)
186 {
187 	struct icmp6hdr *icmp6h;
188 	const struct ipv6hdr *ip6h;
189 
190 	icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
191 	if (icmp6h == NULL)
192 		return 0;
193 
194 	ip6h = ipv6_hdr(skb);
195 	icmp6h->icmp6_cksum = 0;
196 	skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
197 	icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
198 					      ipl - ihl, IPPROTO_ICMPV6,
199 					      skb->csum);
200 
201 	skb->ip_summed = CHECKSUM_NONE;
202 
203 	return 1;
204 }
205 
206 static int tcf_csum_ipv4_tcp(struct sk_buff *skb, unsigned int ihl,
207 			     unsigned int ipl)
208 {
209 	struct tcphdr *tcph;
210 	const struct iphdr *iph;
211 
212 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
213 		return 1;
214 
215 	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
216 	if (tcph == NULL)
217 		return 0;
218 
219 	iph = ip_hdr(skb);
220 	tcph->check = 0;
221 	skb->csum = csum_partial(tcph, ipl - ihl, 0);
222 	tcph->check = tcp_v4_check(ipl - ihl,
223 				   iph->saddr, iph->daddr, skb->csum);
224 
225 	skb->ip_summed = CHECKSUM_NONE;
226 
227 	return 1;
228 }
229 
230 static int tcf_csum_ipv6_tcp(struct sk_buff *skb, unsigned int ihl,
231 			     unsigned int ipl)
232 {
233 	struct tcphdr *tcph;
234 	const struct ipv6hdr *ip6h;
235 
236 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
237 		return 1;
238 
239 	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
240 	if (tcph == NULL)
241 		return 0;
242 
243 	ip6h = ipv6_hdr(skb);
244 	tcph->check = 0;
245 	skb->csum = csum_partial(tcph, ipl - ihl, 0);
246 	tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
247 				      ipl - ihl, IPPROTO_TCP,
248 				      skb->csum);
249 
250 	skb->ip_summed = CHECKSUM_NONE;
251 
252 	return 1;
253 }
254 
255 static int tcf_csum_ipv4_udp(struct sk_buff *skb, unsigned int ihl,
256 			     unsigned int ipl, int udplite)
257 {
258 	struct udphdr *udph;
259 	const struct iphdr *iph;
260 	u16 ul;
261 
262 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
263 		return 1;
264 
265 	/*
266 	 * Support both UDP and UDPLITE checksum algorithms, Don't use
267 	 * udph->len to get the real length without any protocol check,
268 	 * UDPLITE uses udph->len for another thing,
269 	 * Use iph->tot_len, or just ipl.
270 	 */
271 
272 	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
273 	if (udph == NULL)
274 		return 0;
275 
276 	iph = ip_hdr(skb);
277 	ul = ntohs(udph->len);
278 
279 	if (udplite || udph->check) {
280 
281 		udph->check = 0;
282 
283 		if (udplite) {
284 			if (ul == 0)
285 				skb->csum = csum_partial(udph, ipl - ihl, 0);
286 			else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
287 				skb->csum = csum_partial(udph, ul, 0);
288 			else
289 				goto ignore_obscure_skb;
290 		} else {
291 			if (ul != ipl - ihl)
292 				goto ignore_obscure_skb;
293 
294 			skb->csum = csum_partial(udph, ul, 0);
295 		}
296 
297 		udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
298 						ul, iph->protocol,
299 						skb->csum);
300 
301 		if (!udph->check)
302 			udph->check = CSUM_MANGLED_0;
303 	}
304 
305 	skb->ip_summed = CHECKSUM_NONE;
306 
307 ignore_obscure_skb:
308 	return 1;
309 }
310 
311 static int tcf_csum_ipv6_udp(struct sk_buff *skb, unsigned int ihl,
312 			     unsigned int ipl, int udplite)
313 {
314 	struct udphdr *udph;
315 	const struct ipv6hdr *ip6h;
316 	u16 ul;
317 
318 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
319 		return 1;
320 
321 	/*
322 	 * Support both UDP and UDPLITE checksum algorithms, Don't use
323 	 * udph->len to get the real length without any protocol check,
324 	 * UDPLITE uses udph->len for another thing,
325 	 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
326 	 */
327 
328 	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
329 	if (udph == NULL)
330 		return 0;
331 
332 	ip6h = ipv6_hdr(skb);
333 	ul = ntohs(udph->len);
334 
335 	udph->check = 0;
336 
337 	if (udplite) {
338 		if (ul == 0)
339 			skb->csum = csum_partial(udph, ipl - ihl, 0);
340 
341 		else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
342 			skb->csum = csum_partial(udph, ul, 0);
343 
344 		else
345 			goto ignore_obscure_skb;
346 	} else {
347 		if (ul != ipl - ihl)
348 			goto ignore_obscure_skb;
349 
350 		skb->csum = csum_partial(udph, ul, 0);
351 	}
352 
353 	udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
354 				      udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
355 				      skb->csum);
356 
357 	if (!udph->check)
358 		udph->check = CSUM_MANGLED_0;
359 
360 	skb->ip_summed = CHECKSUM_NONE;
361 
362 ignore_obscure_skb:
363 	return 1;
364 }
365 
366 static int tcf_csum_sctp(struct sk_buff *skb, unsigned int ihl,
367 			 unsigned int ipl)
368 {
369 	struct sctphdr *sctph;
370 
371 	if (skb_is_gso(skb) && skb_is_gso_sctp(skb))
372 		return 1;
373 
374 	sctph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*sctph));
375 	if (!sctph)
376 		return 0;
377 
378 	sctph->checksum = sctp_compute_cksum(skb,
379 					     skb_network_offset(skb) + ihl);
380 	skb->ip_summed = CHECKSUM_NONE;
381 	skb->csum_not_inet = 0;
382 
383 	return 1;
384 }
385 
386 static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
387 {
388 	const struct iphdr *iph;
389 	int ntkoff;
390 
391 	ntkoff = skb_network_offset(skb);
392 
393 	if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
394 		goto fail;
395 
396 	iph = ip_hdr(skb);
397 
398 	switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
399 	case IPPROTO_ICMP:
400 		if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
401 			if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
402 						ntohs(iph->tot_len)))
403 				goto fail;
404 		break;
405 	case IPPROTO_IGMP:
406 		if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
407 			if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
408 						ntohs(iph->tot_len)))
409 				goto fail;
410 		break;
411 	case IPPROTO_TCP:
412 		if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
413 			if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
414 					       ntohs(iph->tot_len)))
415 				goto fail;
416 		break;
417 	case IPPROTO_UDP:
418 		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
419 			if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
420 					       ntohs(iph->tot_len), 0))
421 				goto fail;
422 		break;
423 	case IPPROTO_UDPLITE:
424 		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
425 			if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
426 					       ntohs(iph->tot_len), 1))
427 				goto fail;
428 		break;
429 	case IPPROTO_SCTP:
430 		if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
431 		    !tcf_csum_sctp(skb, iph->ihl * 4, ntohs(iph->tot_len)))
432 			goto fail;
433 		break;
434 	}
435 
436 	if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
437 		if (skb_try_make_writable(skb, sizeof(*iph) + ntkoff))
438 			goto fail;
439 
440 		ip_send_check(ip_hdr(skb));
441 	}
442 
443 	return 1;
444 
445 fail:
446 	return 0;
447 }
448 
449 static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh, unsigned int ixhl,
450 				 unsigned int *pl)
451 {
452 	int off, len, optlen;
453 	unsigned char *xh = (void *)ip6xh;
454 
455 	off = sizeof(*ip6xh);
456 	len = ixhl - off;
457 
458 	while (len > 1) {
459 		switch (xh[off]) {
460 		case IPV6_TLV_PAD1:
461 			optlen = 1;
462 			break;
463 		case IPV6_TLV_JUMBO:
464 			optlen = xh[off + 1] + 2;
465 			if (optlen != 6 || len < 6 || (off & 3) != 2)
466 				/* wrong jumbo option length/alignment */
467 				return 0;
468 			*pl = ntohl(*(__be32 *)(xh + off + 2));
469 			goto done;
470 		default:
471 			optlen = xh[off + 1] + 2;
472 			if (optlen > len)
473 				/* ignore obscure options */
474 				goto done;
475 			break;
476 		}
477 		off += optlen;
478 		len -= optlen;
479 	}
480 
481 done:
482 	return 1;
483 }
484 
485 static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
486 {
487 	struct ipv6hdr *ip6h;
488 	struct ipv6_opt_hdr *ip6xh;
489 	unsigned int hl, ixhl;
490 	unsigned int pl;
491 	int ntkoff;
492 	u8 nexthdr;
493 
494 	ntkoff = skb_network_offset(skb);
495 
496 	hl = sizeof(*ip6h);
497 
498 	if (!pskb_may_pull(skb, hl + ntkoff))
499 		goto fail;
500 
501 	ip6h = ipv6_hdr(skb);
502 
503 	pl = ntohs(ip6h->payload_len);
504 	nexthdr = ip6h->nexthdr;
505 
506 	do {
507 		switch (nexthdr) {
508 		case NEXTHDR_FRAGMENT:
509 			goto ignore_skb;
510 		case NEXTHDR_ROUTING:
511 		case NEXTHDR_HOP:
512 		case NEXTHDR_DEST:
513 			if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
514 				goto fail;
515 			ip6xh = (void *)(skb_network_header(skb) + hl);
516 			ixhl = ipv6_optlen(ip6xh);
517 			if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
518 				goto fail;
519 			ip6xh = (void *)(skb_network_header(skb) + hl);
520 			if ((nexthdr == NEXTHDR_HOP) &&
521 			    !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
522 				goto fail;
523 			nexthdr = ip6xh->nexthdr;
524 			hl += ixhl;
525 			break;
526 		case IPPROTO_ICMPV6:
527 			if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
528 				if (!tcf_csum_ipv6_icmp(skb,
529 							hl, pl + sizeof(*ip6h)))
530 					goto fail;
531 			goto done;
532 		case IPPROTO_TCP:
533 			if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
534 				if (!tcf_csum_ipv6_tcp(skb,
535 						       hl, pl + sizeof(*ip6h)))
536 					goto fail;
537 			goto done;
538 		case IPPROTO_UDP:
539 			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
540 				if (!tcf_csum_ipv6_udp(skb, hl,
541 						       pl + sizeof(*ip6h), 0))
542 					goto fail;
543 			goto done;
544 		case IPPROTO_UDPLITE:
545 			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
546 				if (!tcf_csum_ipv6_udp(skb, hl,
547 						       pl + sizeof(*ip6h), 1))
548 					goto fail;
549 			goto done;
550 		case IPPROTO_SCTP:
551 			if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
552 			    !tcf_csum_sctp(skb, hl, pl + sizeof(*ip6h)))
553 				goto fail;
554 			goto done;
555 		default:
556 			goto ignore_skb;
557 		}
558 	} while (pskb_may_pull(skb, hl + 1 + ntkoff));
559 
560 done:
561 ignore_skb:
562 	return 1;
563 
564 fail:
565 	return 0;
566 }
567 
568 static int tcf_csum_act(struct sk_buff *skb, const struct tc_action *a,
569 			struct tcf_result *res)
570 {
571 	struct tcf_csum *p = to_tcf_csum(a);
572 	bool orig_vlan_tag_present = false;
573 	unsigned int vlan_hdr_count = 0;
574 	struct tcf_csum_params *params;
575 	u32 update_flags;
576 	__be16 protocol;
577 	int action;
578 
579 	params = rcu_dereference_bh(p->params);
580 
581 	tcf_lastuse_update(&p->tcf_tm);
582 	bstats_cpu_update(this_cpu_ptr(p->common.cpu_bstats), skb);
583 
584 	action = READ_ONCE(p->tcf_action);
585 	if (unlikely(action == TC_ACT_SHOT))
586 		goto drop;
587 
588 	update_flags = params->update_flags;
589 	protocol = tc_skb_protocol(skb);
590 again:
591 	switch (protocol) {
592 	case cpu_to_be16(ETH_P_IP):
593 		if (!tcf_csum_ipv4(skb, update_flags))
594 			goto drop;
595 		break;
596 	case cpu_to_be16(ETH_P_IPV6):
597 		if (!tcf_csum_ipv6(skb, update_flags))
598 			goto drop;
599 		break;
600 	case cpu_to_be16(ETH_P_8021AD): /* fall through */
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 	qstats_drop_inc(this_cpu_ptr(p->common.cpu_qstats));
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(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