xref: /openbmc/linux/net/sched/act_csum.c (revision 842ed298)
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 	return ret;
114 put_chain:
115 	if (goto_ch)
116 		tcf_chain_put_by_act(goto_ch);
117 release_idr:
118 	tcf_idr_release(*a, bind);
119 	return err;
120 }
121 
122 /**
123  * tcf_csum_skb_nextlayer - Get next layer pointer
124  * @skb: sk_buff to use
125  * @ihl: previous summed headers length
126  * @ipl: complete packet length
127  * @jhl: next header length
128  *
129  * Check the expected next layer availability in the specified sk_buff.
130  * Return the next layer pointer if pass, NULL otherwise.
131  */
132 static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
133 				    unsigned int ihl, unsigned int ipl,
134 				    unsigned int jhl)
135 {
136 	int ntkoff = skb_network_offset(skb);
137 	int hl = ihl + jhl;
138 
139 	if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
140 	    skb_try_make_writable(skb, hl + ntkoff))
141 		return NULL;
142 	else
143 		return (void *)(skb_network_header(skb) + ihl);
144 }
145 
146 static int tcf_csum_ipv4_icmp(struct sk_buff *skb, unsigned int ihl,
147 			      unsigned int ipl)
148 {
149 	struct icmphdr *icmph;
150 
151 	icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
152 	if (icmph == NULL)
153 		return 0;
154 
155 	icmph->checksum = 0;
156 	skb->csum = csum_partial(icmph, ipl - ihl, 0);
157 	icmph->checksum = csum_fold(skb->csum);
158 
159 	skb->ip_summed = CHECKSUM_NONE;
160 
161 	return 1;
162 }
163 
164 static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
165 			      unsigned int ihl, unsigned int ipl)
166 {
167 	struct igmphdr *igmph;
168 
169 	igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
170 	if (igmph == NULL)
171 		return 0;
172 
173 	igmph->csum = 0;
174 	skb->csum = csum_partial(igmph, ipl - ihl, 0);
175 	igmph->csum = csum_fold(skb->csum);
176 
177 	skb->ip_summed = CHECKSUM_NONE;
178 
179 	return 1;
180 }
181 
182 static int tcf_csum_ipv6_icmp(struct sk_buff *skb, unsigned int ihl,
183 			      unsigned int ipl)
184 {
185 	struct icmp6hdr *icmp6h;
186 	const struct ipv6hdr *ip6h;
187 
188 	icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
189 	if (icmp6h == NULL)
190 		return 0;
191 
192 	ip6h = ipv6_hdr(skb);
193 	icmp6h->icmp6_cksum = 0;
194 	skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
195 	icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
196 					      ipl - ihl, IPPROTO_ICMPV6,
197 					      skb->csum);
198 
199 	skb->ip_summed = CHECKSUM_NONE;
200 
201 	return 1;
202 }
203 
204 static int tcf_csum_ipv4_tcp(struct sk_buff *skb, unsigned int ihl,
205 			     unsigned int ipl)
206 {
207 	struct tcphdr *tcph;
208 	const struct iphdr *iph;
209 
210 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
211 		return 1;
212 
213 	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
214 	if (tcph == NULL)
215 		return 0;
216 
217 	iph = ip_hdr(skb);
218 	tcph->check = 0;
219 	skb->csum = csum_partial(tcph, ipl - ihl, 0);
220 	tcph->check = tcp_v4_check(ipl - ihl,
221 				   iph->saddr, iph->daddr, skb->csum);
222 
223 	skb->ip_summed = CHECKSUM_NONE;
224 
225 	return 1;
226 }
227 
228 static int tcf_csum_ipv6_tcp(struct sk_buff *skb, unsigned int ihl,
229 			     unsigned int ipl)
230 {
231 	struct tcphdr *tcph;
232 	const struct ipv6hdr *ip6h;
233 
234 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
235 		return 1;
236 
237 	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
238 	if (tcph == NULL)
239 		return 0;
240 
241 	ip6h = ipv6_hdr(skb);
242 	tcph->check = 0;
243 	skb->csum = csum_partial(tcph, ipl - ihl, 0);
244 	tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
245 				      ipl - ihl, IPPROTO_TCP,
246 				      skb->csum);
247 
248 	skb->ip_summed = CHECKSUM_NONE;
249 
250 	return 1;
251 }
252 
253 static int tcf_csum_ipv4_udp(struct sk_buff *skb, unsigned int ihl,
254 			     unsigned int ipl, int udplite)
255 {
256 	struct udphdr *udph;
257 	const struct iphdr *iph;
258 	u16 ul;
259 
260 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
261 		return 1;
262 
263 	/*
264 	 * Support both UDP and UDPLITE checksum algorithms, Don't use
265 	 * udph->len to get the real length without any protocol check,
266 	 * UDPLITE uses udph->len for another thing,
267 	 * Use iph->tot_len, or just ipl.
268 	 */
269 
270 	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
271 	if (udph == NULL)
272 		return 0;
273 
274 	iph = ip_hdr(skb);
275 	ul = ntohs(udph->len);
276 
277 	if (udplite || udph->check) {
278 
279 		udph->check = 0;
280 
281 		if (udplite) {
282 			if (ul == 0)
283 				skb->csum = csum_partial(udph, ipl - ihl, 0);
284 			else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
285 				skb->csum = csum_partial(udph, ul, 0);
286 			else
287 				goto ignore_obscure_skb;
288 		} else {
289 			if (ul != ipl - ihl)
290 				goto ignore_obscure_skb;
291 
292 			skb->csum = csum_partial(udph, ul, 0);
293 		}
294 
295 		udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
296 						ul, iph->protocol,
297 						skb->csum);
298 
299 		if (!udph->check)
300 			udph->check = CSUM_MANGLED_0;
301 	}
302 
303 	skb->ip_summed = CHECKSUM_NONE;
304 
305 ignore_obscure_skb:
306 	return 1;
307 }
308 
309 static int tcf_csum_ipv6_udp(struct sk_buff *skb, unsigned int ihl,
310 			     unsigned int ipl, int udplite)
311 {
312 	struct udphdr *udph;
313 	const struct ipv6hdr *ip6h;
314 	u16 ul;
315 
316 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
317 		return 1;
318 
319 	/*
320 	 * Support both UDP and UDPLITE checksum algorithms, Don't use
321 	 * udph->len to get the real length without any protocol check,
322 	 * UDPLITE uses udph->len for another thing,
323 	 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
324 	 */
325 
326 	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
327 	if (udph == NULL)
328 		return 0;
329 
330 	ip6h = ipv6_hdr(skb);
331 	ul = ntohs(udph->len);
332 
333 	udph->check = 0;
334 
335 	if (udplite) {
336 		if (ul == 0)
337 			skb->csum = csum_partial(udph, ipl - ihl, 0);
338 
339 		else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
340 			skb->csum = csum_partial(udph, ul, 0);
341 
342 		else
343 			goto ignore_obscure_skb;
344 	} else {
345 		if (ul != ipl - ihl)
346 			goto ignore_obscure_skb;
347 
348 		skb->csum = csum_partial(udph, ul, 0);
349 	}
350 
351 	udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
352 				      udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
353 				      skb->csum);
354 
355 	if (!udph->check)
356 		udph->check = CSUM_MANGLED_0;
357 
358 	skb->ip_summed = CHECKSUM_NONE;
359 
360 ignore_obscure_skb:
361 	return 1;
362 }
363 
364 static int tcf_csum_sctp(struct sk_buff *skb, unsigned int ihl,
365 			 unsigned int ipl)
366 {
367 	struct sctphdr *sctph;
368 
369 	if (skb_is_gso(skb) && skb_is_gso_sctp(skb))
370 		return 1;
371 
372 	sctph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*sctph));
373 	if (!sctph)
374 		return 0;
375 
376 	sctph->checksum = sctp_compute_cksum(skb,
377 					     skb_network_offset(skb) + ihl);
378 	skb->ip_summed = CHECKSUM_NONE;
379 	skb->csum_not_inet = 0;
380 
381 	return 1;
382 }
383 
384 static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
385 {
386 	const struct iphdr *iph;
387 	int ntkoff;
388 
389 	ntkoff = skb_network_offset(skb);
390 
391 	if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
392 		goto fail;
393 
394 	iph = ip_hdr(skb);
395 
396 	switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
397 	case IPPROTO_ICMP:
398 		if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
399 			if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
400 						ntohs(iph->tot_len)))
401 				goto fail;
402 		break;
403 	case IPPROTO_IGMP:
404 		if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
405 			if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
406 						ntohs(iph->tot_len)))
407 				goto fail;
408 		break;
409 	case IPPROTO_TCP:
410 		if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
411 			if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
412 					       ntohs(iph->tot_len)))
413 				goto fail;
414 		break;
415 	case IPPROTO_UDP:
416 		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
417 			if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
418 					       ntohs(iph->tot_len), 0))
419 				goto fail;
420 		break;
421 	case IPPROTO_UDPLITE:
422 		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
423 			if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
424 					       ntohs(iph->tot_len), 1))
425 				goto fail;
426 		break;
427 	case IPPROTO_SCTP:
428 		if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
429 		    !tcf_csum_sctp(skb, iph->ihl * 4, ntohs(iph->tot_len)))
430 			goto fail;
431 		break;
432 	}
433 
434 	if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
435 		if (skb_try_make_writable(skb, sizeof(*iph) + ntkoff))
436 			goto fail;
437 
438 		ip_send_check(ip_hdr(skb));
439 	}
440 
441 	return 1;
442 
443 fail:
444 	return 0;
445 }
446 
447 static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh, unsigned int ixhl,
448 				 unsigned int *pl)
449 {
450 	int off, len, optlen;
451 	unsigned char *xh = (void *)ip6xh;
452 
453 	off = sizeof(*ip6xh);
454 	len = ixhl - off;
455 
456 	while (len > 1) {
457 		switch (xh[off]) {
458 		case IPV6_TLV_PAD1:
459 			optlen = 1;
460 			break;
461 		case IPV6_TLV_JUMBO:
462 			optlen = xh[off + 1] + 2;
463 			if (optlen != 6 || len < 6 || (off & 3) != 2)
464 				/* wrong jumbo option length/alignment */
465 				return 0;
466 			*pl = ntohl(*(__be32 *)(xh + off + 2));
467 			goto done;
468 		default:
469 			optlen = xh[off + 1] + 2;
470 			if (optlen > len)
471 				/* ignore obscure options */
472 				goto done;
473 			break;
474 		}
475 		off += optlen;
476 		len -= optlen;
477 	}
478 
479 done:
480 	return 1;
481 }
482 
483 static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
484 {
485 	struct ipv6hdr *ip6h;
486 	struct ipv6_opt_hdr *ip6xh;
487 	unsigned int hl, ixhl;
488 	unsigned int pl;
489 	int ntkoff;
490 	u8 nexthdr;
491 
492 	ntkoff = skb_network_offset(skb);
493 
494 	hl = sizeof(*ip6h);
495 
496 	if (!pskb_may_pull(skb, hl + ntkoff))
497 		goto fail;
498 
499 	ip6h = ipv6_hdr(skb);
500 
501 	pl = ntohs(ip6h->payload_len);
502 	nexthdr = ip6h->nexthdr;
503 
504 	do {
505 		switch (nexthdr) {
506 		case NEXTHDR_FRAGMENT:
507 			goto ignore_skb;
508 		case NEXTHDR_ROUTING:
509 		case NEXTHDR_HOP:
510 		case NEXTHDR_DEST:
511 			if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
512 				goto fail;
513 			ip6xh = (void *)(skb_network_header(skb) + hl);
514 			ixhl = ipv6_optlen(ip6xh);
515 			if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
516 				goto fail;
517 			ip6xh = (void *)(skb_network_header(skb) + hl);
518 			if ((nexthdr == NEXTHDR_HOP) &&
519 			    !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
520 				goto fail;
521 			nexthdr = ip6xh->nexthdr;
522 			hl += ixhl;
523 			break;
524 		case IPPROTO_ICMPV6:
525 			if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
526 				if (!tcf_csum_ipv6_icmp(skb,
527 							hl, pl + sizeof(*ip6h)))
528 					goto fail;
529 			goto done;
530 		case IPPROTO_TCP:
531 			if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
532 				if (!tcf_csum_ipv6_tcp(skb,
533 						       hl, pl + sizeof(*ip6h)))
534 					goto fail;
535 			goto done;
536 		case IPPROTO_UDP:
537 			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
538 				if (!tcf_csum_ipv6_udp(skb, hl,
539 						       pl + sizeof(*ip6h), 0))
540 					goto fail;
541 			goto done;
542 		case IPPROTO_UDPLITE:
543 			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
544 				if (!tcf_csum_ipv6_udp(skb, hl,
545 						       pl + sizeof(*ip6h), 1))
546 					goto fail;
547 			goto done;
548 		case IPPROTO_SCTP:
549 			if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
550 			    !tcf_csum_sctp(skb, hl, pl + sizeof(*ip6h)))
551 				goto fail;
552 			goto done;
553 		default:
554 			goto ignore_skb;
555 		}
556 	} while (pskb_may_pull(skb, hl + 1 + ntkoff));
557 
558 done:
559 ignore_skb:
560 	return 1;
561 
562 fail:
563 	return 0;
564 }
565 
566 static int tcf_csum_act(struct sk_buff *skb, const struct tc_action *a,
567 			struct tcf_result *res)
568 {
569 	struct tcf_csum *p = to_tcf_csum(a);
570 	bool orig_vlan_tag_present = false;
571 	unsigned int vlan_hdr_count = 0;
572 	struct tcf_csum_params *params;
573 	u32 update_flags;
574 	__be16 protocol;
575 	int action;
576 
577 	params = rcu_dereference_bh(p->params);
578 
579 	tcf_lastuse_update(&p->tcf_tm);
580 	tcf_action_update_bstats(&p->common, skb);
581 
582 	action = READ_ONCE(p->tcf_action);
583 	if (unlikely(action == TC_ACT_SHOT))
584 		goto drop;
585 
586 	update_flags = params->update_flags;
587 	protocol = skb_protocol(skb, false);
588 again:
589 	switch (protocol) {
590 	case cpu_to_be16(ETH_P_IP):
591 		if (!tcf_csum_ipv4(skb, update_flags))
592 			goto drop;
593 		break;
594 	case cpu_to_be16(ETH_P_IPV6):
595 		if (!tcf_csum_ipv6(skb, update_flags))
596 			goto drop;
597 		break;
598 	case cpu_to_be16(ETH_P_8021AD):
599 		fallthrough;
600 	case cpu_to_be16(ETH_P_8021Q):
601 		if (skb_vlan_tag_present(skb) && !orig_vlan_tag_present) {
602 			protocol = skb->protocol;
603 			orig_vlan_tag_present = true;
604 		} else {
605 			struct vlan_hdr *vlan = (struct vlan_hdr *)skb->data;
606 
607 			protocol = vlan->h_vlan_encapsulated_proto;
608 			skb_pull(skb, VLAN_HLEN);
609 			skb_reset_network_header(skb);
610 			vlan_hdr_count++;
611 		}
612 		goto again;
613 	}
614 
615 out:
616 	/* Restore the skb for the pulled VLAN tags */
617 	while (vlan_hdr_count--) {
618 		skb_push(skb, VLAN_HLEN);
619 		skb_reset_network_header(skb);
620 	}
621 
622 	return action;
623 
624 drop:
625 	tcf_action_inc_drop_qstats(&p->common);
626 	action = TC_ACT_SHOT;
627 	goto out;
628 }
629 
630 static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind,
631 			 int ref)
632 {
633 	unsigned char *b = skb_tail_pointer(skb);
634 	struct tcf_csum *p = to_tcf_csum(a);
635 	struct tcf_csum_params *params;
636 	struct tc_csum opt = {
637 		.index   = p->tcf_index,
638 		.refcnt  = refcount_read(&p->tcf_refcnt) - ref,
639 		.bindcnt = atomic_read(&p->tcf_bindcnt) - bind,
640 	};
641 	struct tcf_t t;
642 
643 	spin_lock_bh(&p->tcf_lock);
644 	params = rcu_dereference_protected(p->params,
645 					   lockdep_is_held(&p->tcf_lock));
646 	opt.action = p->tcf_action;
647 	opt.update_flags = params->update_flags;
648 
649 	if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
650 		goto nla_put_failure;
651 
652 	tcf_tm_dump(&t, &p->tcf_tm);
653 	if (nla_put_64bit(skb, TCA_CSUM_TM, sizeof(t), &t, TCA_CSUM_PAD))
654 		goto nla_put_failure;
655 	spin_unlock_bh(&p->tcf_lock);
656 
657 	return skb->len;
658 
659 nla_put_failure:
660 	spin_unlock_bh(&p->tcf_lock);
661 	nlmsg_trim(skb, b);
662 	return -1;
663 }
664 
665 static void tcf_csum_cleanup(struct tc_action *a)
666 {
667 	struct tcf_csum *p = to_tcf_csum(a);
668 	struct tcf_csum_params *params;
669 
670 	params = rcu_dereference_protected(p->params, 1);
671 	if (params)
672 		kfree_rcu(params, rcu);
673 }
674 
675 static int tcf_csum_walker(struct net *net, struct sk_buff *skb,
676 			   struct netlink_callback *cb, int type,
677 			   const struct tc_action_ops *ops,
678 			   struct netlink_ext_ack *extack)
679 {
680 	struct tc_action_net *tn = net_generic(net, csum_net_id);
681 
682 	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
683 }
684 
685 static int tcf_csum_search(struct net *net, struct tc_action **a, u32 index)
686 {
687 	struct tc_action_net *tn = net_generic(net, csum_net_id);
688 
689 	return tcf_idr_search(tn, a, index);
690 }
691 
692 static size_t tcf_csum_get_fill_size(const struct tc_action *act)
693 {
694 	return nla_total_size(sizeof(struct tc_csum));
695 }
696 
697 static struct tc_action_ops act_csum_ops = {
698 	.kind		= "csum",
699 	.id		= TCA_ID_CSUM,
700 	.owner		= THIS_MODULE,
701 	.act		= tcf_csum_act,
702 	.dump		= tcf_csum_dump,
703 	.init		= tcf_csum_init,
704 	.cleanup	= tcf_csum_cleanup,
705 	.walk		= tcf_csum_walker,
706 	.lookup		= tcf_csum_search,
707 	.get_fill_size  = tcf_csum_get_fill_size,
708 	.size		= sizeof(struct tcf_csum),
709 };
710 
711 static __net_init int csum_init_net(struct net *net)
712 {
713 	struct tc_action_net *tn = net_generic(net, csum_net_id);
714 
715 	return tc_action_net_init(net, tn, &act_csum_ops);
716 }
717 
718 static void __net_exit csum_exit_net(struct list_head *net_list)
719 {
720 	tc_action_net_exit(net_list, csum_net_id);
721 }
722 
723 static struct pernet_operations csum_net_ops = {
724 	.init = csum_init_net,
725 	.exit_batch = csum_exit_net,
726 	.id   = &csum_net_id,
727 	.size = sizeof(struct tc_action_net),
728 };
729 
730 MODULE_DESCRIPTION("Checksum updating actions");
731 MODULE_LICENSE("GPL");
732 
733 static int __init csum_init_module(void)
734 {
735 	return tcf_register_action(&act_csum_ops, &csum_net_ops);
736 }
737 
738 static void __exit csum_cleanup_module(void)
739 {
740 	tcf_unregister_action(&act_csum_ops, &csum_net_ops);
741 }
742 
743 module_init(csum_init_module);
744 module_exit(csum_cleanup_module);
745