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Linux/net/sched/act_csum.c

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  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 

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