net/sched/act_csum.c

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