xref: /openbmc/linux/net/sched/act_csum.c (revision 0c7beb2d) 
1 /*
2  * Checksum updating actions
3  *
4  * Copyright (c) 2010 Gregoire Baron <baronchon@n7mm.org>
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License as published by the Free
8  * Software Foundation; either version 2 of the License, or (at your option)
9  * any later version.
10  *
11  */
12 
13 #include <linux/types.h>
14 #include <linux/init.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/spinlock.h>
18 
19 #include <linux/netlink.h>
20 #include <net/netlink.h>
21 #include <linux/rtnetlink.h>
22 
23 #include <linux/skbuff.h>
24 
25 #include <net/ip.h>
26 #include <net/ipv6.h>
27 #include <net/icmp.h>
28 #include <linux/icmpv6.h>
29 #include <linux/igmp.h>
30 #include <net/tcp.h>
31 #include <net/udp.h>
32 #include <net/ip6_checksum.h>
33 #include <net/sctp/checksum.h>
34 
35 #include <net/act_api.h>
36 #include <net/pkt_cls.h>
37 
38 #include <linux/tc_act/tc_csum.h>
39 #include <net/tc_act/tc_csum.h>
40 
41 static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
42 	[TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
43 };
44 
45 static unsigned int csum_net_id;
46 static struct tc_action_ops act_csum_ops;
47 
48 static int tcf_csum_init(struct net *net, struct nlattr *nla,
49 			 struct nlattr *est, struct tc_action **a, int ovr,
50 			 int bind, bool rtnl_held, struct tcf_proto *tp,
51 			 struct netlink_ext_ack *extack)
52 {
53 	struct tc_action_net *tn = net_generic(net, csum_net_id);
54 	struct tcf_csum_params *params_new;
55 	struct nlattr *tb[TCA_CSUM_MAX + 1];
56 	struct tcf_chain *goto_ch = NULL;
57 	struct tc_csum *parm;
58 	struct tcf_csum *p;
59 	int ret = 0, err;
60 
61 	if (nla == NULL)
62 		return -EINVAL;
63 
64 	err = nla_parse_nested(tb, TCA_CSUM_MAX, nla, csum_policy, NULL);
65 	if (err < 0)
66 		return err;
67 
68 	if (tb[TCA_CSUM_PARMS] == NULL)
69 		return -EINVAL;
70 	parm = nla_data(tb[TCA_CSUM_PARMS]);
71 
72 	err = tcf_idr_check_alloc(tn, &parm->index, a, bind);
73 	if (!err) {
74 		ret = tcf_idr_create(tn, parm->index, est, a,
75 				     &act_csum_ops, bind, true);
76 		if (ret) {
77 			tcf_idr_cleanup(tn, parm->index);
78 			return ret;
79 		}
80 		ret = ACT_P_CREATED;
81 	} else if (err > 0) {
82 		if (bind)/* dont override defaults */
83 			return 0;
84 		if (!ovr) {
85 			tcf_idr_release(*a, bind);
86 			return -EEXIST;
87 		}
88 	} else {
89 		return err;
90 	}
91 
92 	err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
93 	if (err < 0)
94 		goto release_idr;
95 
96 	p = to_tcf_csum(*a);
97 
98 	params_new = kzalloc(sizeof(*params_new), GFP_KERNEL);
99 	if (unlikely(!params_new)) {
100 		err = -ENOMEM;
101 		goto put_chain;
102 	}
103 	params_new->update_flags = parm->update_flags;
104 
105 	spin_lock_bh(&p->tcf_lock);
106 	goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
107 	rcu_swap_protected(p->params, params_new,
108 			   lockdep_is_held(&p->tcf_lock));
109 	spin_unlock_bh(&p->tcf_lock);
110 
111 	if (goto_ch)
112 		tcf_chain_put_by_act(goto_ch);
113 	if (params_new)
114 		kfree_rcu(params_new, rcu);
115 
116 	if (ret == ACT_P_CREATED)
117 		tcf_idr_insert(tn, *a);
118 
119 	return ret;
120 put_chain:
121 	if (goto_ch)
122 		tcf_chain_put_by_act(goto_ch);
123 release_idr:
124 	tcf_idr_release(*a, bind);
125 	return err;
126 }
127 
128 /**
129  * tcf_csum_skb_nextlayer - Get next layer pointer
130  * @skb: sk_buff to use
131  * @ihl: previous summed headers length
132  * @ipl: complete packet length
133  * @jhl: next header length
134  *
135  * Check the expected next layer availability in the specified sk_buff.
136  * Return the next layer pointer if pass, NULL otherwise.
137  */
138 static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
139 				    unsigned int ihl, unsigned int ipl,
140 				    unsigned int jhl)
141 {
142 	int ntkoff = skb_network_offset(skb);
143 	int hl = ihl + jhl;
144 
145 	if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
146 	    skb_try_make_writable(skb, hl + ntkoff))
147 		return NULL;
148 	else
149 		return (void *)(skb_network_header(skb) + ihl);
150 }
151 
152 static int tcf_csum_ipv4_icmp(struct sk_buff *skb, unsigned int ihl,
153 			      unsigned int ipl)
154 {
155 	struct icmphdr *icmph;
156 
157 	icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
158 	if (icmph == NULL)
159 		return 0;
160 
161 	icmph->checksum = 0;
162 	skb->csum = csum_partial(icmph, ipl - ihl, 0);
163 	icmph->checksum = csum_fold(skb->csum);
164 
165 	skb->ip_summed = CHECKSUM_NONE;
166 
167 	return 1;
168 }
169 
170 static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
171 			      unsigned int ihl, unsigned int ipl)
172 {
173 	struct igmphdr *igmph;
174 
175 	igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
176 	if (igmph == NULL)
177 		return 0;
178 
179 	igmph->csum = 0;
180 	skb->csum = csum_partial(igmph, ipl - ihl, 0);
181 	igmph->csum = csum_fold(skb->csum);
182 
183 	skb->ip_summed = CHECKSUM_NONE;
184 
185 	return 1;
186 }
187 
188 static int tcf_csum_ipv6_icmp(struct sk_buff *skb, unsigned int ihl,
189 			      unsigned int ipl)
190 {
191 	struct icmp6hdr *icmp6h;
192 	const struct ipv6hdr *ip6h;
193 
194 	icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
195 	if (icmp6h == NULL)
196 		return 0;
197 
198 	ip6h = ipv6_hdr(skb);
199 	icmp6h->icmp6_cksum = 0;
200 	skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
201 	icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
202 					      ipl - ihl, IPPROTO_ICMPV6,
203 					      skb->csum);
204 
205 	skb->ip_summed = CHECKSUM_NONE;
206 
207 	return 1;
208 }
209 
210 static int tcf_csum_ipv4_tcp(struct sk_buff *skb, unsigned int ihl,
211 			     unsigned int ipl)
212 {
213 	struct tcphdr *tcph;
214 	const struct iphdr *iph;
215 
216 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
217 		return 1;
218 
219 	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
220 	if (tcph == NULL)
221 		return 0;
222 
223 	iph = ip_hdr(skb);
224 	tcph->check = 0;
225 	skb->csum = csum_partial(tcph, ipl - ihl, 0);
226 	tcph->check = tcp_v4_check(ipl - ihl,
227 				   iph->saddr, iph->daddr, skb->csum);
228 
229 	skb->ip_summed = CHECKSUM_NONE;
230 
231 	return 1;
232 }
233 
234 static int tcf_csum_ipv6_tcp(struct sk_buff *skb, unsigned int ihl,
235 			     unsigned int ipl)
236 {
237 	struct tcphdr *tcph;
238 	const struct ipv6hdr *ip6h;
239 
240 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
241 		return 1;
242 
243 	tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
244 	if (tcph == NULL)
245 		return 0;
246 
247 	ip6h = ipv6_hdr(skb);
248 	tcph->check = 0;
249 	skb->csum = csum_partial(tcph, ipl - ihl, 0);
250 	tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
251 				      ipl - ihl, IPPROTO_TCP,
252 				      skb->csum);
253 
254 	skb->ip_summed = CHECKSUM_NONE;
255 
256 	return 1;
257 }
258 
259 static int tcf_csum_ipv4_udp(struct sk_buff *skb, unsigned int ihl,
260 			     unsigned int ipl, int udplite)
261 {
262 	struct udphdr *udph;
263 	const struct iphdr *iph;
264 	u16 ul;
265 
266 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
267 		return 1;
268 
269 	/*
270 	 * Support both UDP and UDPLITE checksum algorithms, Don't use
271 	 * udph->len to get the real length without any protocol check,
272 	 * UDPLITE uses udph->len for another thing,
273 	 * Use iph->tot_len, or just ipl.
274 	 */
275 
276 	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
277 	if (udph == NULL)
278 		return 0;
279 
280 	iph = ip_hdr(skb);
281 	ul = ntohs(udph->len);
282 
283 	if (udplite || udph->check) {
284 
285 		udph->check = 0;
286 
287 		if (udplite) {
288 			if (ul == 0)
289 				skb->csum = csum_partial(udph, ipl - ihl, 0);
290 			else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
291 				skb->csum = csum_partial(udph, ul, 0);
292 			else
293 				goto ignore_obscure_skb;
294 		} else {
295 			if (ul != ipl - ihl)
296 				goto ignore_obscure_skb;
297 
298 			skb->csum = csum_partial(udph, ul, 0);
299 		}
300 
301 		udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
302 						ul, iph->protocol,
303 						skb->csum);
304 
305 		if (!udph->check)
306 			udph->check = CSUM_MANGLED_0;
307 	}
308 
309 	skb->ip_summed = CHECKSUM_NONE;
310 
311 ignore_obscure_skb:
312 	return 1;
313 }
314 
315 static int tcf_csum_ipv6_udp(struct sk_buff *skb, unsigned int ihl,
316 			     unsigned int ipl, int udplite)
317 {
318 	struct udphdr *udph;
319 	const struct ipv6hdr *ip6h;
320 	u16 ul;
321 
322 	if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
323 		return 1;
324 
325 	/*
326 	 * Support both UDP and UDPLITE checksum algorithms, Don't use
327 	 * udph->len to get the real length without any protocol check,
328 	 * UDPLITE uses udph->len for another thing,
329 	 * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
330 	 */
331 
332 	udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
333 	if (udph == NULL)
334 		return 0;
335 
336 	ip6h = ipv6_hdr(skb);
337 	ul = ntohs(udph->len);
338 
339 	udph->check = 0;
340 
341 	if (udplite) {
342 		if (ul == 0)
343 			skb->csum = csum_partial(udph, ipl - ihl, 0);
344 
345 		else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
346 			skb->csum = csum_partial(udph, ul, 0);
347 
348 		else
349 			goto ignore_obscure_skb;
350 	} else {
351 		if (ul != ipl - ihl)
352 			goto ignore_obscure_skb;
353 
354 		skb->csum = csum_partial(udph, ul, 0);
355 	}
356 
357 	udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
358 				      udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
359 				      skb->csum);
360 
361 	if (!udph->check)
362 		udph->check = CSUM_MANGLED_0;
363 
364 	skb->ip_summed = CHECKSUM_NONE;
365 
366 ignore_obscure_skb:
367 	return 1;
368 }
369 
370 static int tcf_csum_sctp(struct sk_buff *skb, unsigned int ihl,
371 			 unsigned int ipl)
372 {
373 	struct sctphdr *sctph;
374 
375 	if (skb_is_gso(skb) && skb_is_gso_sctp(skb))
376 		return 1;
377 
378 	sctph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*sctph));
379 	if (!sctph)
380 		return 0;
381 
382 	sctph->checksum = sctp_compute_cksum(skb,
383 					     skb_network_offset(skb) + ihl);
384 	skb->ip_summed = CHECKSUM_NONE;
385 	skb->csum_not_inet = 0;
386 
387 	return 1;
388 }
389 
390 static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
391 {
392 	const struct iphdr *iph;
393 	int ntkoff;
394 
395 	ntkoff = skb_network_offset(skb);
396 
397 	if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
398 		goto fail;
399 
400 	iph = ip_hdr(skb);
401 
402 	switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
403 	case IPPROTO_ICMP:
404 		if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
405 			if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
406 						ntohs(iph->tot_len)))
407 				goto fail;
408 		break;
409 	case IPPROTO_IGMP:
410 		if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
411 			if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
412 						ntohs(iph->tot_len)))
413 				goto fail;
414 		break;
415 	case IPPROTO_TCP:
416 		if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
417 			if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
418 					       ntohs(iph->tot_len)))
419 				goto fail;
420 		break;
421 	case IPPROTO_UDP:
422 		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
423 			if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
424 					       ntohs(iph->tot_len), 0))
425 				goto fail;
426 		break;
427 	case IPPROTO_UDPLITE:
428 		if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
429 			if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
430 					       ntohs(iph->tot_len), 1))
431 				goto fail;
432 		break;
433 	case IPPROTO_SCTP:
434 		if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
435 		    !tcf_csum_sctp(skb, iph->ihl * 4, ntohs(iph->tot_len)))
436 			goto fail;
437 		break;
438 	}
439 
440 	if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
441 		if (skb_try_make_writable(skb, sizeof(*iph) + ntkoff))
442 			goto fail;
443 
444 		ip_send_check(ip_hdr(skb));
445 	}
446 
447 	return 1;
448 
449 fail:
450 	return 0;
451 }
452 
453 static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh, unsigned int ixhl,
454 				 unsigned int *pl)
455 {
456 	int off, len, optlen;
457 	unsigned char *xh = (void *)ip6xh;
458 
459 	off = sizeof(*ip6xh);
460 	len = ixhl - off;
461 
462 	while (len > 1) {
463 		switch (xh[off]) {
464 		case IPV6_TLV_PAD1:
465 			optlen = 1;
466 			break;
467 		case IPV6_TLV_JUMBO:
468 			optlen = xh[off + 1] + 2;
469 			if (optlen != 6 || len < 6 || (off & 3) != 2)
470 				/* wrong jumbo option length/alignment */
471 				return 0;
472 			*pl = ntohl(*(__be32 *)(xh + off + 2));
473 			goto done;
474 		default:
475 			optlen = xh[off + 1] + 2;
476 			if (optlen > len)
477 				/* ignore obscure options */
478 				goto done;
479 			break;
480 		}
481 		off += optlen;
482 		len -= optlen;
483 	}
484 
485 done:
486 	return 1;
487 }
488 
489 static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
490 {
491 	struct ipv6hdr *ip6h;
492 	struct ipv6_opt_hdr *ip6xh;
493 	unsigned int hl, ixhl;
494 	unsigned int pl;
495 	int ntkoff;
496 	u8 nexthdr;
497 
498 	ntkoff = skb_network_offset(skb);
499 
500 	hl = sizeof(*ip6h);
501 
502 	if (!pskb_may_pull(skb, hl + ntkoff))
503 		goto fail;
504 
505 	ip6h = ipv6_hdr(skb);
506 
507 	pl = ntohs(ip6h->payload_len);
508 	nexthdr = ip6h->nexthdr;
509 
510 	do {
511 		switch (nexthdr) {
512 		case NEXTHDR_FRAGMENT:
513 			goto ignore_skb;
514 		case NEXTHDR_ROUTING:
515 		case NEXTHDR_HOP:
516 		case NEXTHDR_DEST:
517 			if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
518 				goto fail;
519 			ip6xh = (void *)(skb_network_header(skb) + hl);
520 			ixhl = ipv6_optlen(ip6xh);
521 			if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
522 				goto fail;
523 			ip6xh = (void *)(skb_network_header(skb) + hl);
524 			if ((nexthdr == NEXTHDR_HOP) &&
525 			    !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
526 				goto fail;
527 			nexthdr = ip6xh->nexthdr;
528 			hl += ixhl;
529 			break;
530 		case IPPROTO_ICMPV6:
531 			if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
532 				if (!tcf_csum_ipv6_icmp(skb,
533 							hl, pl + sizeof(*ip6h)))
534 					goto fail;
535 			goto done;
536 		case IPPROTO_TCP:
537 			if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
538 				if (!tcf_csum_ipv6_tcp(skb,
539 						       hl, pl + sizeof(*ip6h)))
540 					goto fail;
541 			goto done;
542 		case IPPROTO_UDP:
543 			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
544 				if (!tcf_csum_ipv6_udp(skb, hl,
545 						       pl + sizeof(*ip6h), 0))
546 					goto fail;
547 			goto done;
548 		case IPPROTO_UDPLITE:
549 			if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
550 				if (!tcf_csum_ipv6_udp(skb, hl,
551 						       pl + sizeof(*ip6h), 1))
552 					goto fail;
553 			goto done;
554 		case IPPROTO_SCTP:
555 			if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
556 			    !tcf_csum_sctp(skb, hl, pl + sizeof(*ip6h)))
557 				goto fail;
558 			goto done;
559 		default:
560 			goto ignore_skb;
561 		}
562 	} while (pskb_may_pull(skb, hl + 1 + ntkoff));
563 
564 done:
565 ignore_skb:
566 	return 1;
567 
568 fail:
569 	return 0;
570 }
571 
572 static int tcf_csum_act(struct sk_buff *skb, const struct tc_action *a,
573 			struct tcf_result *res)
574 {
575 	struct tcf_csum *p = to_tcf_csum(a);
576 	bool orig_vlan_tag_present = false;
577 	unsigned int vlan_hdr_count = 0;
578 	struct tcf_csum_params *params;
579 	u32 update_flags;
580 	__be16 protocol;
581 	int action;
582 
583 	params = rcu_dereference_bh(p->params);
584 
585 	tcf_lastuse_update(&p->tcf_tm);
586 	bstats_cpu_update(this_cpu_ptr(p->common.cpu_bstats), skb);
587 
588 	action = READ_ONCE(p->tcf_action);
589 	if (unlikely(action == TC_ACT_SHOT))
590 		goto drop;
591 
592 	update_flags = params->update_flags;
593 	protocol = tc_skb_protocol(skb);
594 again:
595 	switch (protocol) {
596 	case cpu_to_be16(ETH_P_IP):
597 		if (!tcf_csum_ipv4(skb, update_flags))
598 			goto drop;
599 		break;
600 	case cpu_to_be16(ETH_P_IPV6):
601 		if (!tcf_csum_ipv6(skb, update_flags))
602 			goto drop;
603 		break;
604 	case cpu_to_be16(ETH_P_8021AD): /* fall through */
605 	case cpu_to_be16(ETH_P_8021Q):
606 		if (skb_vlan_tag_present(skb) && !orig_vlan_tag_present) {
607 			protocol = skb->protocol;
608 			orig_vlan_tag_present = true;
609 		} else {
610 			struct vlan_hdr *vlan = (struct vlan_hdr *)skb->data;
611 
612 			protocol = vlan->h_vlan_encapsulated_proto;
613 			skb_pull(skb, VLAN_HLEN);
614 			skb_reset_network_header(skb);
615 			vlan_hdr_count++;
616 		}
617 		goto again;
618 	}
619 
620 out:
621 	/* Restore the skb for the pulled VLAN tags */
622 	while (vlan_hdr_count--) {
623 		skb_push(skb, VLAN_HLEN);
624 		skb_reset_network_header(skb);
625 	}
626 
627 	return action;
628 
629 drop:
630 	qstats_drop_inc(this_cpu_ptr(p->common.cpu_qstats));
631 	action = TC_ACT_SHOT;
632 	goto out;
633 }
634 
635 static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind,
636 			 int ref)
637 {
638 	unsigned char *b = skb_tail_pointer(skb);
639 	struct tcf_csum *p = to_tcf_csum(a);
640 	struct tcf_csum_params *params;
641 	struct tc_csum opt = {
642 		.index   = p->tcf_index,
643 		.refcnt  = refcount_read(&p->tcf_refcnt) - ref,
644 		.bindcnt = atomic_read(&p->tcf_bindcnt) - bind,
645 	};
646 	struct tcf_t t;
647 
648 	spin_lock_bh(&p->tcf_lock);
649 	params = rcu_dereference_protected(p->params,
650 					   lockdep_is_held(&p->tcf_lock));
651 	opt.action = p->tcf_action;
652 	opt.update_flags = params->update_flags;
653 
654 	if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
655 		goto nla_put_failure;
656 
657 	tcf_tm_dump(&t, &p->tcf_tm);
658 	if (nla_put_64bit(skb, TCA_CSUM_TM, sizeof(t), &t, TCA_CSUM_PAD))
659 		goto nla_put_failure;
660 	spin_unlock_bh(&p->tcf_lock);
661 
662 	return skb->len;
663 
664 nla_put_failure:
665 	spin_unlock_bh(&p->tcf_lock);
666 	nlmsg_trim(skb, b);
667 	return -1;
668 }
669 
670 static void tcf_csum_cleanup(struct tc_action *a)
671 {
672 	struct tcf_csum *p = to_tcf_csum(a);
673 	struct tcf_csum_params *params;
674 
675 	params = rcu_dereference_protected(p->params, 1);
676 	if (params)
677 		kfree_rcu(params, rcu);
678 }
679 
680 static int tcf_csum_walker(struct net *net, struct sk_buff *skb,
681 			   struct netlink_callback *cb, int type,
682 			   const struct tc_action_ops *ops,
683 			   struct netlink_ext_ack *extack)
684 {
685 	struct tc_action_net *tn = net_generic(net, csum_net_id);
686 
687 	return tcf_generic_walker(tn, skb, cb, type, ops, extack);
688 }
689 
690 static int tcf_csum_search(struct net *net, struct tc_action **a, u32 index)
691 {
692 	struct tc_action_net *tn = net_generic(net, csum_net_id);
693 
694 	return tcf_idr_search(tn, a, index);
695 }
696 
697 static size_t tcf_csum_get_fill_size(const struct tc_action *act)
698 {
699 	return nla_total_size(sizeof(struct tc_csum));
700 }
701 
702 static struct tc_action_ops act_csum_ops = {
703 	.kind		= "csum",
704 	.id		= TCA_ID_CSUM,
705 	.owner		= THIS_MODULE,
706 	.act		= tcf_csum_act,
707 	.dump		= tcf_csum_dump,
708 	.init		= tcf_csum_init,
709 	.cleanup	= tcf_csum_cleanup,
710 	.walk		= tcf_csum_walker,
711 	.lookup		= tcf_csum_search,
712 	.get_fill_size  = tcf_csum_get_fill_size,
713 	.size		= sizeof(struct tcf_csum),
714 };
715 
716 static __net_init int csum_init_net(struct net *net)
717 {
718 	struct tc_action_net *tn = net_generic(net, csum_net_id);
719 
720 	return tc_action_net_init(tn, &act_csum_ops);
721 }
722 
723 static void __net_exit csum_exit_net(struct list_head *net_list)
724 {
725 	tc_action_net_exit(net_list, csum_net_id);
726 }
727 
728 static struct pernet_operations csum_net_ops = {
729 	.init = csum_init_net,
730 	.exit_batch = csum_exit_net,
731 	.id   = &csum_net_id,
732 	.size = sizeof(struct tc_action_net),
733 };
734 
735 MODULE_DESCRIPTION("Checksum updating actions");
736 MODULE_LICENSE("GPL");
737 
738 static int __init csum_init_module(void)
739 {
740 	return tcf_register_action(&act_csum_ops, &csum_net_ops);
741 }
742 
743 static void __exit csum_cleanup_module(void)
744 {
745 	tcf_unregister_action(&act_csum_ops, &csum_net_ops);
746 }
747 
748 module_init(csum_init_module);
749 module_exit(csum_cleanup_module);
750