xref: /linux/net/sched/act_csum.c (revision 37744feebc086908fd89760650f458ab19071750)
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 			 u32 flags, 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 	u32 index;
56 
57 	if (nla == NULL)
58 		return -EINVAL;
59 
60 	err = nla_parse_nested_deprecated(tb, TCA_CSUM_MAX, nla, csum_policy,
61 					  NULL);
62 	if (err < 0)
63 		return err;
64 
65 	if (tb[TCA_CSUM_PARMS] == NULL)
66 		return -EINVAL;
67 	parm = nla_data(tb[TCA_CSUM_PARMS]);
68 	index = parm->index;
69 	err = tcf_idr_check_alloc(tn, &index, a, bind);
70 	if (!err) {
71 		ret = tcf_idr_create_from_flags(tn, index, est, a,
72 						&act_csum_ops, bind, flags);
73 		if (ret) {
74 			tcf_idr_cleanup(tn, index);
75 			return ret;
76 		}
77 		ret = ACT_P_CREATED;
78 	} else if (err > 0) {
79 		if (bind)/* dont override defaults */
80 			return 0;
81 		if (!ovr) {
82 			tcf_idr_release(*a, bind);
83 			return -EEXIST;
84 		}
85 	} else {
86 		return err;
87 	}
88 
89 	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
90 	if (err < 0)
91 		goto release_idr;
92 
93 	p = to_tcf_csum(*a);
94 
95 	params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
96 	if (unlikely(!params_new)) {
97 		err = -ENOMEM;
98 		goto put_chain;
99 	}
100 	params_new->update_flags = parm->update_flags;
101 
102 	spin_lock_bh(&p->tcf_lock);
103 	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
104 	params_new = rcu_replace_pointer(p->params, params_new,
105 					 lockdep_is_held(&p->tcf_lock));
106 	spin_unlock_bh(&p->tcf_lock);
107 
108 	if (goto_ch)
109 		tcf_chain_put_by_act(goto_ch);
110 	if (params_new)
111 		kfree_rcu(params_new, rcu);
112 
113 	if (ret == ACT_P_CREATED)
114 		tcf_idr_insert(tn, *a);
115 
116 	return ret;
117 put_chain:
118 	if (goto_ch)
119 		tcf_chain_put_by_act(goto_ch);
120 release_idr:
121 	tcf_idr_release(*a, bind);
122 	return err;
123 }
124 
125 /**
126  * tcf_csum_skb_nextlayer - Get next layer pointer
127  * @skb: sk_buff to use
128  * @ihl: previous summed headers length
129  * @ipl: complete packet length
130  * @jhl: next header length
131  *
132  * Check the expected next layer availability in the specified sk_buff.
133  * Return the next layer pointer if pass, NULL otherwise.
134  */
135 static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
136 				    unsigned int ihl, unsigned int ipl,
137 				    unsigned int jhl)
138 {
139 	int ntkoff = skb_network_offset(skb);
140 	int hl = ihl + jhl;
141 
142 	if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
143 	    skb_try_make_writable(skb, hl + ntkoff))
144 		return NULL;
145 	else
146 		return (void *)(skb_network_header(skb) + ihl);
147 }
148 
149 static int tcf_csum_ipv4_icmp(struct sk_buff *skb, unsigned int ihl,
150 			      unsigned int ipl)
151 {
152 	struct icmphdr *icmph;
153 
154 	icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
155 	if (icmph == NULL)
156 		return 0;
157 
158 	icmph->checksum = 0;
159 	skb->csum = csum_partial(icmph, ipl - ihl, 0);
160 	icmph->checksum = csum_fold(skb->csum);
161 
162 	skb->ip_summed = CHECKSUM_NONE;
163 
164 	return 1;
165 }
166 
167 static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
168 			      unsigned int ihl, unsigned int ipl)
169 {
170 	struct igmphdr *igmph;
171 
172 	igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
173 	if (igmph == NULL)
174 		return 0;
175 
176 	igmph->csum = 0;
177 	skb->csum = csum_partial(igmph, ipl - ihl, 0);
178 	igmph->csum = csum_fold(skb->csum);
179 
180 	skb->ip_summed = CHECKSUM_NONE;
181 
182 	return 1;
183 }
184 
185 static int tcf_csum_ipv6_icmp(struct sk_buff *skb, unsigned int ihl,
186 			      unsigned int ipl)
187 {
188 	struct icmp6hdr *icmp6h;
189 	const struct ipv6hdr *ip6h;
190 
191 	icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
192 	if (icmp6h == NULL)
193 		return 0;
194 
195 	ip6h = ipv6_hdr(skb);
196 	icmp6h->icmp6_cksum = 0;
197 	skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
198 	icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
199 					      ipl - ihl, IPPROTO_ICMPV6,
200 					      skb->csum);
201 
202 	skb->ip_summed = CHECKSUM_NONE;
203 
204 	return 1;
205 }
206 
207 static int tcf_csum_ipv4_tcp(struct sk_buff *skb, unsigned int ihl,
208 			     unsigned int ipl)
209 {
210 	struct tcphdr *tcph;
211 	const struct iphdr *iph;
212 
213 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
214 		return 1;
215 
216 	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
217 	if (tcph == NULL)
218 		return 0;
219 
220 	iph = ip_hdr(skb);
221 	tcph->check = 0;
222 	skb->csum = csum_partial(tcph, ipl - ihl, 0);
223 	tcph->check = tcp_v4_check(ipl - ihl,
224 				   iph->saddr, iph->daddr, skb->csum);
225 
226 	skb->ip_summed = CHECKSUM_NONE;
227 
228 	return 1;
229 }
230 
231 static int tcf_csum_ipv6_tcp(struct sk_buff *skb, unsigned int ihl,
232 			     unsigned int ipl)
233 {
234 	struct tcphdr *tcph;
235 	const struct ipv6hdr *ip6h;
236 
237 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
238 		return 1;
239 
240 	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
241 	if (tcph == NULL)
242 		return 0;
243 
244 	ip6h = ipv6_hdr(skb);
245 	tcph->check = 0;
246 	skb->csum = csum_partial(tcph, ipl - ihl, 0);
247 	tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
248 				      ipl - ihl, IPPROTO_TCP,
249 				      skb->csum);
250 
251 	skb->ip_summed = CHECKSUM_NONE;
252 
253 	return 1;
254 }
255 
256 static int tcf_csum_ipv4_udp(struct sk_buff *skb, unsigned int ihl,
257 			     unsigned int ipl, int udplite)
258 {
259 	struct udphdr *udph;
260 	const struct iphdr *iph;
261 	u16 ul;
262 
263 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
264 		return 1;
265 
266 	/*
267 	 * Support both UDP and UDPLITE checksum algorithms, Don't use
268 	 * udph->len to get the real length without any protocol check,
269 	 * UDPLITE uses udph->len for another thing,
270 	 * Use iph->tot_len, or just ipl.
271 	 */
272 
273 	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
274 	if (udph == NULL)
275 		return 0;
276 
277 	iph = ip_hdr(skb);
278 	ul = ntohs(udph->len);
279 
280 	if (udplite || udph->check) {
281 
282 		udph->check = 0;
283 
284 		if (udplite) {
285 			if (ul == 0)
286 				skb->csum = csum_partial(udph, ipl - ihl, 0);
287 			else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
288 				skb->csum = csum_partial(udph, ul, 0);
289 			else
290 				goto ignore_obscure_skb;
291 		} else {
292 			if (ul != ipl - ihl)
293 				goto ignore_obscure_skb;
294 
295 			skb->csum = csum_partial(udph, ul, 0);
296 		}
297 
298 		udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
299 						ul, iph->protocol,
300 						skb->csum);
301 
302 		if (!udph->check)
303 			udph->check = CSUM_MANGLED_0;
304 	}
305 
306 	skb->ip_summed = CHECKSUM_NONE;
307 
308 ignore_obscure_skb:
309 	return 1;
310 }
311 
312 static int tcf_csum_ipv6_udp(struct sk_buff *skb, unsigned int ihl,
313 			     unsigned int ipl, int udplite)
314 {
315 	struct udphdr *udph;
316 	const struct ipv6hdr *ip6h;
317 	u16 ul;
318 
319 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
320 		return 1;
321 
322 	/*
323 	 * Support both UDP and UDPLITE checksum algorithms, Don't use
324 	 * udph->len to get the real length without any protocol check,
325 	 * UDPLITE uses udph->len for another thing,
326 	 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
327 	 */
328 
329 	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
330 	if (udph == NULL)
331 		return 0;
332 
333 	ip6h = ipv6_hdr(skb);
334 	ul = ntohs(udph->len);
335 
336 	udph->check = 0;
337 
338 	if (udplite) {
339 		if (ul == 0)
340 			skb->csum = csum_partial(udph, ipl - ihl, 0);
341 
342 		else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
343 			skb->csum = csum_partial(udph, ul, 0);
344 
345 		else
346 			goto ignore_obscure_skb;
347 	} else {
348 		if (ul != ipl - ihl)
349 			goto ignore_obscure_skb;
350 
351 		skb->csum = csum_partial(udph, ul, 0);
352 	}
353 
354 	udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
355 				      udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
356 				      skb->csum);
357 
358 	if (!udph->check)
359 		udph->check = CSUM_MANGLED_0;
360 
361 	skb->ip_summed = CHECKSUM_NONE;
362 
363 ignore_obscure_skb:
364 	return 1;
365 }
366 
367 static int tcf_csum_sctp(struct sk_buff *skb, unsigned int ihl,
368 			 unsigned int ipl)
369 {
370 	struct sctphdr *sctph;
371 
372 	if (skb_is_gso(skb) && skb_is_gso_sctp(skb))
373 		return 1;
374 
375 	sctph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*sctph));
376 	if (!sctph)
377 		return 0;
378 
379 	sctph->checksum = sctp_compute_cksum(skb,
380 					     skb_network_offset(skb) + ihl);
381 	skb->ip_summed = CHECKSUM_NONE;
382 	skb->csum_not_inet = 0;
383 
384 	return 1;
385 }
386 
387 static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
388 {
389 	const struct iphdr *iph;
390 	int ntkoff;
391 
392 	ntkoff = skb_network_offset(skb);
393 
394 	if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
395 		goto fail;
396 
397 	iph = ip_hdr(skb);
398 
399 	switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
400 	case IPPROTO_ICMP:
401 		if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
402 			if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
403 						ntohs(iph->tot_len)))
404 				goto fail;
405 		break;
406 	case IPPROTO_IGMP:
407 		if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
408 			if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
409 						ntohs(iph->tot_len)))
410 				goto fail;
411 		break;
412 	case IPPROTO_TCP:
413 		if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
414 			if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
415 					       ntohs(iph->tot_len)))
416 				goto fail;
417 		break;
418 	case IPPROTO_UDP:
419 		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
420 			if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
421 					       ntohs(iph->tot_len), 0))
422 				goto fail;
423 		break;
424 	case IPPROTO_UDPLITE:
425 		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
426 			if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
427 					       ntohs(iph->tot_len), 1))
428 				goto fail;
429 		break;
430 	case IPPROTO_SCTP:
431 		if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
432 		    !tcf_csum_sctp(skb, iph->ihl * 4, ntohs(iph->tot_len)))
433 			goto fail;
434 		break;
435 	}
436 
437 	if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
438 		if (skb_try_make_writable(skb, sizeof(*iph) + ntkoff))
439 			goto fail;
440 
441 		ip_send_check(ip_hdr(skb));
442 	}
443 
444 	return 1;
445 
446 fail:
447 	return 0;
448 }
449 
450 static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh, unsigned int ixhl,
451 				 unsigned int *pl)
452 {
453 	int off, len, optlen;
454 	unsigned char *xh = (void *)ip6xh;
455 
456 	off = sizeof(*ip6xh);
457 	len = ixhl - off;
458 
459 	while (len > 1) {
460 		switch (xh[off]) {
461 		case IPV6_TLV_PAD1:
462 			optlen = 1;
463 			break;
464 		case IPV6_TLV_JUMBO:
465 			optlen = xh[off + 1] + 2;
466 			if (optlen != 6 || len < 6 || (off & 3) != 2)
467 				/* wrong jumbo option length/alignment */
468 				return 0;
469 			*pl = ntohl(*(__be32 *)(xh + off + 2));
470 			goto done;
471 		default:
472 			optlen = xh[off + 1] + 2;
473 			if (optlen > len)
474 				/* ignore obscure options */
475 				goto done;
476 			break;
477 		}
478 		off += optlen;
479 		len -= optlen;
480 	}
481 
482 done:
483 	return 1;
484 }
485 
486 static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
487 {
488 	struct ipv6hdr *ip6h;
489 	struct ipv6_opt_hdr *ip6xh;
490 	unsigned int hl, ixhl;
491 	unsigned int pl;
492 	int ntkoff;
493 	u8 nexthdr;
494 
495 	ntkoff = skb_network_offset(skb);
496 
497 	hl = sizeof(*ip6h);
498 
499 	if (!pskb_may_pull(skb, hl + ntkoff))
500 		goto fail;
501 
502 	ip6h = ipv6_hdr(skb);
503 
504 	pl = ntohs(ip6h->payload_len);
505 	nexthdr = ip6h->nexthdr;
506 
507 	do {
508 		switch (nexthdr) {
509 		case NEXTHDR_FRAGMENT:
510 			goto ignore_skb;
511 		case NEXTHDR_ROUTING:
512 		case NEXTHDR_HOP:
513 		case NEXTHDR_DEST:
514 			if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
515 				goto fail;
516 			ip6xh = (void *)(skb_network_header(skb) + hl);
517 			ixhl = ipv6_optlen(ip6xh);
518 			if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
519 				goto fail;
520 			ip6xh = (void *)(skb_network_header(skb) + hl);
521 			if ((nexthdr == NEXTHDR_HOP) &&
522 			    !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
523 				goto fail;
524 			nexthdr = ip6xh->nexthdr;
525 			hl += ixhl;
526 			break;
527 		case IPPROTO_ICMPV6:
528 			if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
529 				if (!tcf_csum_ipv6_icmp(skb,
530 							hl, pl + sizeof(*ip6h)))
531 					goto fail;
532 			goto done;
533 		case IPPROTO_TCP:
534 			if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
535 				if (!tcf_csum_ipv6_tcp(skb,
536 						       hl, pl + sizeof(*ip6h)))
537 					goto fail;
538 			goto done;
539 		case IPPROTO_UDP:
540 			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
541 				if (!tcf_csum_ipv6_udp(skb, hl,
542 						       pl + sizeof(*ip6h), 0))
543 					goto fail;
544 			goto done;
545 		case IPPROTO_UDPLITE:
546 			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
547 				if (!tcf_csum_ipv6_udp(skb, hl,
548 						       pl + sizeof(*ip6h), 1))
549 					goto fail;
550 			goto done;
551 		case IPPROTO_SCTP:
552 			if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
553 			    !tcf_csum_sctp(skb, hl, pl + sizeof(*ip6h)))
554 				goto fail;
555 			goto done;
556 		default:
557 			goto ignore_skb;
558 		}
559 	} while (pskb_may_pull(skb, hl + 1 + ntkoff));
560 
561 done:
562 ignore_skb:
563 	return 1;
564 
565 fail:
566 	return 0;
567 }
568 
569 static int tcf_csum_act(struct sk_buff *skb, const struct tc_action *a,
570 			struct tcf_result *res)
571 {
572 	struct tcf_csum *p = to_tcf_csum(a);
573 	bool orig_vlan_tag_present = false;
574 	unsigned int vlan_hdr_count = 0;
575 	struct tcf_csum_params *params;
576 	u32 update_flags;
577 	__be16 protocol;
578 	int action;
579 
580 	params = rcu_dereference_bh(p->params);
581 
582 	tcf_lastuse_update(&p->tcf_tm);
583 	tcf_action_update_bstats(&p->common, skb);
584 
585 	action = READ_ONCE(p->tcf_action);
586 	if (unlikely(action == TC_ACT_SHOT))
587 		goto drop;
588 
589 	update_flags = params->update_flags;
590 	protocol = tc_skb_protocol(skb);
591 again:
592 	switch (protocol) {
593 	case cpu_to_be16(ETH_P_IP):
594 		if (!tcf_csum_ipv4(skb, update_flags))
595 			goto drop;
596 		break;
597 	case cpu_to_be16(ETH_P_IPV6):
598 		if (!tcf_csum_ipv6(skb, update_flags))
599 			goto drop;
600 		break;
601 	case cpu_to_be16(ETH_P_8021AD): /* fall through */
602 	case cpu_to_be16(ETH_P_8021Q):
603 		if (skb_vlan_tag_present(skb) && !orig_vlan_tag_present) {
604 			protocol = skb->protocol;
605 			orig_vlan_tag_present = true;
606 		} else {
607 			struct vlan_hdr *vlan = (struct vlan_hdr *)skb->data;
608 
609 			protocol = vlan->h_vlan_encapsulated_proto;
610 			skb_pull(skb, VLAN_HLEN);
611 			skb_reset_network_header(skb);
612 			vlan_hdr_count++;
613 		}
614 		goto again;
615 	}
616 
617 out:
618 	/* Restore the skb for the pulled VLAN tags */
619 	while (vlan_hdr_count--) {
620 		skb_push(skb, VLAN_HLEN);
621 		skb_reset_network_header(skb);
622 	}
623 
624 	return action;
625 
626 drop:
627 	tcf_action_inc_drop_qstats(&p->common);
628 	action = TC_ACT_SHOT;
629 	goto out;
630 }
631 
632 static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind,
633 			 int ref)
634 {
635 	unsigned char *b = skb_tail_pointer(skb);
636 	struct tcf_csum *p = to_tcf_csum(a);
637 	struct tcf_csum_params *params;
638 	struct tc_csum opt = {
639 		.index   = p->tcf_index,
640 		.refcnt  = refcount_read(&p->tcf_refcnt) - ref,
641 		.bindcnt = atomic_read(&p->tcf_bindcnt) - bind,
642 	};
643 	struct tcf_t t;
644 
645 	spin_lock_bh(&p->tcf_lock);
646 	params = rcu_dereference_protected(p->params,
647 					   lockdep_is_held(&p->tcf_lock));
648 	opt.action = p->tcf_action;
649 	opt.update_flags = params->update_flags;
650 
651 	if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
652 		goto nla_put_failure;
653 
654 	tcf_tm_dump(&t, &p->tcf_tm);
655 	if (nla_put_64bit(skb, TCA_CSUM_TM, sizeof(t), &t, TCA_CSUM_PAD))
656 		goto nla_put_failure;
657 	spin_unlock_bh(&p->tcf_lock);
658 
659 	return skb->len;
660 
661 nla_put_failure:
662 	spin_unlock_bh(&p->tcf_lock);
663 	nlmsg_trim(skb, b);
664 	return -1;
665 }
666 
667 static void tcf_csum_cleanup(struct tc_action *a)
668 {
669 	struct tcf_csum *p = to_tcf_csum(a);
670 	struct tcf_csum_params *params;
671 
672 	params = rcu_dereference_protected(p->params, 1);
673 	if (params)
674 		kfree_rcu(params, rcu);
675 }
676 
677 static int tcf_csum_walker(struct net *net, struct sk_buff *skb,
678 			   struct netlink_callback *cb, int type,
679 			   const struct tc_action_ops *ops,
680 			   struct netlink_ext_ack *extack)
681 {
682 	struct tc_action_net *tn = net_generic(net, csum_net_id);
683 
684 	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
685 }
686 
687 static int tcf_csum_search(struct net *net, struct tc_action **a, u32 index)
688 {
689 	struct tc_action_net *tn = net_generic(net, csum_net_id);
690 
691 	return tcf_idr_search(tn, a, index);
692 }
693 
694 static size_t tcf_csum_get_fill_size(const struct tc_action *act)
695 {
696 	return nla_total_size(sizeof(struct tc_csum));
697 }
698 
699 static struct tc_action_ops act_csum_ops = {
700 	.kind		= "csum",
701 	.id		= TCA_ID_CSUM,
702 	.owner		= THIS_MODULE,
703 	.act		= tcf_csum_act,
704 	.dump		= tcf_csum_dump,
705 	.init		= tcf_csum_init,
706 	.cleanup	= tcf_csum_cleanup,
707 	.walk		= tcf_csum_walker,
708 	.lookup		= tcf_csum_search,
709 	.get_fill_size  = tcf_csum_get_fill_size,
710 	.size		= sizeof(struct tcf_csum),
711 };
712 
713 static __net_init int csum_init_net(struct net *net)
714 {
715 	struct tc_action_net *tn = net_generic(net, csum_net_id);
716 
717 	return tc_action_net_init(net, tn, &act_csum_ops);
718 }
719 
720 static void __net_exit csum_exit_net(struct list_head *net_list)
721 {
722 	tc_action_net_exit(net_list, csum_net_id);
723 }
724 
725 static struct pernet_operations csum_net_ops = {
726 	.init = csum_init_net,
727 	.exit_batch = csum_exit_net,
728 	.id   = &csum_net_id,
729 	.size = sizeof(struct tc_action_net),
730 };
731 
732 MODULE_DESCRIPTION("Checksum updating actions");
733 MODULE_LICENSE("GPL");
734 
735 static int __init csum_init_module(void)
736 {
737 	return tcf_register_action(&act_csum_ops, &csum_net_ops);
738 }
739 
740 static void __exit csum_cleanup_module(void)
741 {
742 	tcf_unregister_action(&act_csum_ops, &csum_net_ops);
743 }
744 
745 module_init(csum_init_module);
746 module_exit(csum_cleanup_module);
747