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 #define CSUM_TAB_MASK 15
  41
  42 static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
  43         [TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
  44 };
  45
  46 static unsigned int csum_net_id;
  47 static struct tc_action_ops act_csum_ops;
  48
  49 static int tcf_csum_init(struct net *net, struct nlattr *nla,
  50                          struct nlattr *est, struct tc_action **a, int ovr,
  51                          int bind)
  52 {
  53         struct tc_action_net *tn = net_generic(net, csum_net_id);
  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);
  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         if (!tcf_hash_check(tn, parm->index, a, bind)) {
  71                 ret = tcf_hash_create(tn, parm->index, est, a,
  72                                       &act_csum_ops, bind, false);
  73                 if (ret)
  74                         return ret;
  75                 ret = ACT_P_CREATED;
  76         } else {
  77                 if (bind)/* dont override defaults */
  78                         return 0;
  79                 tcf_hash_release(*a, bind);
  80                 if (!ovr)
  81                         return -EEXIST;
  82         }
  83
  84         p = to_tcf_csum(*a);
  85         spin_lock_bh(&p->tcf_lock);
  86         p->tcf_action = parm->action;
  87         p->update_flags = parm->update_flags;
  88         spin_unlock_bh(&p->tcf_lock);
  89
  90         if (ret == ACT_P_CREATED)
  91                 tcf_hash_insert(tn, *a);
  92
  93         return ret;
  94 }
  95
  96 /**
  97  * tcf_csum_skb_nextlayer - Get next layer pointer
  98  * @skb: sk_buff to use
  99  * @ihl: previous summed headers length
 100  * @ipl: complete packet length
 101  * @jhl: next header length
 102  *
 103  * Check the expected next layer availability in the specified sk_buff.
 104  * Return the next layer pointer if pass, NULL otherwise.
 105  */
 106 static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
 107                                     unsigned int ihl, unsigned int ipl,
 108                                     unsigned int jhl)
 109 {
 110         int ntkoff = skb_network_offset(skb);
 111         int hl = ihl + jhl;
 112
 113         if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
 114             skb_try_make_writable(skb, hl + ntkoff))
 115                 return NULL;
 116         else
 117                 return (void *)(skb_network_header(skb) + ihl);
 118 }
 119
 120 static int tcf_csum_ipv4_icmp(struct sk_buff *skb, unsigned int ihl,
 121                               unsigned int ipl)
 122 {
 123         struct icmphdr *icmph;
 124
 125         icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
 126         if (icmph == NULL)
 127                 return 0;
 128
 129         icmph->checksum = 0;
 130         skb->csum = csum_partial(icmph, ipl - ihl, 0);
 131         icmph->checksum = csum_fold(skb->csum);
 132
 133         skb->ip_summed = CHECKSUM_NONE;
 134
 135         return 1;
 136 }
 137
 138 static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
 139                               unsigned int ihl, unsigned int ipl)
 140 {
 141         struct igmphdr *igmph;
 142
 143         igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
 144         if (igmph == NULL)
 145                 return 0;
 146
 147         igmph->csum = 0;
 148         skb->csum = csum_partial(igmph, ipl - ihl, 0);
 149         igmph->csum = csum_fold(skb->csum);
 150
 151         skb->ip_summed = CHECKSUM_NONE;
 152
 153         return 1;
 154 }
 155
 156 static int tcf_csum_ipv6_icmp(struct sk_buff *skb, unsigned int ihl,
 157                               unsigned int ipl)
 158 {
 159         struct icmp6hdr *icmp6h;
 160         const struct ipv6hdr *ip6h;
 161
 162         icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
 163         if (icmp6h == NULL)
 164                 return 0;
 165
 166         ip6h = ipv6_hdr(skb);
 167         icmp6h->icmp6_cksum = 0;
 168         skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
 169         icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
 170                                               ipl - ihl, IPPROTO_ICMPV6,
 171                                               skb->csum);
 172
 173         skb->ip_summed = CHECKSUM_NONE;
 174
 175         return 1;
 176 }
 177
 178 static int tcf_csum_ipv4_tcp(struct sk_buff *skb, unsigned int ihl,
 179                              unsigned int ipl)
 180 {
 181         struct tcphdr *tcph;
 182         const struct iphdr *iph;
 183
 184         if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 185                 return 1;
 186
 187         tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
 188         if (tcph == NULL)
 189                 return 0;
 190
 191         iph = ip_hdr(skb);
 192         tcph->check = 0;
 193         skb->csum = csum_partial(tcph, ipl - ihl, 0);
 194         tcph->check = tcp_v4_check(ipl - ihl,
 195                                    iph->saddr, iph->daddr, skb->csum);
 196
 197         skb->ip_summed = CHECKSUM_NONE;
 198
 199         return 1;
 200 }
 201
 202 static int tcf_csum_ipv6_tcp(struct sk_buff *skb, unsigned int ihl,
 203                              unsigned int ipl)
 204 {
 205         struct tcphdr *tcph;
 206         const struct ipv6hdr *ip6h;
 207
 208         if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
 209                 return 1;
 210
 211         tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
 212         if (tcph == NULL)
 213                 return 0;
 214
 215         ip6h = ipv6_hdr(skb);
 216         tcph->check = 0;
 217         skb->csum = csum_partial(tcph, ipl - ihl, 0);
 218         tcph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
 219                                       ipl - ihl, IPPROTO_TCP,
 220                                       skb->csum);
 221
 222         skb->ip_summed = CHECKSUM_NONE;
 223
 224         return 1;
 225 }
 226
 227 static int tcf_csum_ipv4_udp(struct sk_buff *skb, unsigned int ihl,
 228                              unsigned int ipl, int udplite)
 229 {
 230         struct udphdr *udph;
 231         const struct iphdr *iph;
 232         u16 ul;
 233
 234         if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 235                 return 1;
 236
 237         /*
 238          * Support both UDP and UDPLITE checksum algorithms, Don't use
 239          * udph->len to get the real length without any protocol check,
 240          * UDPLITE uses udph->len for another thing,
 241          * Use iph->tot_len, or just ipl.
 242          */
 243
 244         udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
 245         if (udph == NULL)
 246                 return 0;
 247
 248         iph = ip_hdr(skb);
 249         ul = ntohs(udph->len);
 250
 251         if (udplite || udph->check) {
 252
 253                 udph->check = 0;
 254
 255                 if (udplite) {
 256                         if (ul == 0)
 257                                 skb->csum = csum_partial(udph, ipl - ihl, 0);
 258                         else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
 259                                 skb->csum = csum_partial(udph, ul, 0);
 260                         else
 261                                 goto ignore_obscure_skb;
 262                 } else {
 263                         if (ul != ipl - ihl)
 264                                 goto ignore_obscure_skb;
 265
 266                         skb->csum = csum_partial(udph, ul, 0);
 267                 }
 268
 269                 udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
 270                                                 ul, iph->protocol,
 271                                                 skb->csum);
 272
 273                 if (!udph->check)
 274                         udph->check = CSUM_MANGLED_0;
 275         }
 276
 277         skb->ip_summed = CHECKSUM_NONE;
 278
 279 ignore_obscure_skb:
 280         return 1;
 281 }
 282
 283 static int tcf_csum_ipv6_udp(struct sk_buff *skb, unsigned int ihl,
 284                              unsigned int ipl, int udplite)
 285 {
 286         struct udphdr *udph;
 287         const struct ipv6hdr *ip6h;
 288         u16 ul;
 289
 290         if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_UDP)
 291                 return 1;
 292
 293         /*
 294          * Support both UDP and UDPLITE checksum algorithms, Don't use
 295          * udph->len to get the real length without any protocol check,
 296          * UDPLITE uses udph->len for another thing,
 297          * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
 298          */
 299
 300         udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
 301         if (udph == NULL)
 302                 return 0;
 303
 304         ip6h = ipv6_hdr(skb);
 305         ul = ntohs(udph->len);
 306
 307         udph->check = 0;
 308
 309         if (udplite) {
 310                 if (ul == 0)
 311                         skb->csum = csum_partial(udph, ipl - ihl, 0);
 312
 313                 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
 314                         skb->csum = csum_partial(udph, ul, 0);
 315
 316                 else
 317                         goto ignore_obscure_skb;
 318         } else {
 319                 if (ul != ipl - ihl)
 320                         goto ignore_obscure_skb;
 321
 322                 skb->csum = csum_partial(udph, ul, 0);
 323         }
 324
 325         udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
 326                                       udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
 327                                       skb->csum);
 328
 329         if (!udph->check)
 330                 udph->check = CSUM_MANGLED_0;
 331
 332         skb->ip_summed = CHECKSUM_NONE;
 333
 334 ignore_obscure_skb:
 335         return 1;
 336 }
 337
 338 static int tcf_csum_sctp(struct sk_buff *skb, unsigned int ihl,
 339                          unsigned int ipl)
 340 {
 341         struct sctphdr *sctph;
 342
 343         if (skb_is_gso(skb) && skb_shinfo(skb)->gso_type & SKB_GSO_SCTP)
 344                 return 1;
 345
 346         sctph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*sctph));
 347         if (!sctph)
 348                 return 0;
 349
 350         sctph->checksum = sctp_compute_cksum(skb,
 351                                              skb_network_offset(skb) + ihl);
 352         skb->ip_summed = CHECKSUM_NONE;
 353
 354         return 1;
 355 }
 356
 357 static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
 358 {
 359         const struct iphdr *iph;
 360         int ntkoff;
 361
 362         ntkoff = skb_network_offset(skb);
 363
 364         if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
 365                 goto fail;
 366
 367         iph = ip_hdr(skb);
 368
 369         switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
 370         case IPPROTO_ICMP:
 371                 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
 372                         if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
 373                                                 ntohs(iph->tot_len)))
 374                                 goto fail;
 375                 break;
 376         case IPPROTO_IGMP:
 377                 if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
 378                         if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
 379                                                 ntohs(iph->tot_len)))
 380                                 goto fail;
 381                 break;
 382         case IPPROTO_TCP:
 383                 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
 384                         if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
 385                                                ntohs(iph->tot_len)))
 386                                 goto fail;
 387                 break;
 388         case IPPROTO_UDP:
 389                 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
 390                         if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
 391                                                ntohs(iph->tot_len), 0))
 392                                 goto fail;
 393                 break;
 394         case IPPROTO_UDPLITE:
 395                 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
 396                         if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
 397                                                ntohs(iph->tot_len), 1))
 398                                 goto fail;
 399                 break;
 400         case IPPROTO_SCTP:
 401                 if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
 402                     !tcf_csum_sctp(skb, iph->ihl * 4, ntohs(iph->tot_len)))
 403                         goto fail;
 404                 break;
 405         }
 406
 407         if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
 408                 if (skb_try_make_writable(skb, sizeof(*iph) + ntkoff))
 409                         goto fail;
 410
 411                 ip_send_check(ip_hdr(skb));
 412         }
 413
 414         return 1;
 415
 416 fail:
 417         return 0;
 418 }
 419
 420 static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh, unsigned int ixhl,
 421                                  unsigned int *pl)
 422 {
 423         int off, len, optlen;
 424         unsigned char *xh = (void *)ip6xh;
 425
 426         off = sizeof(*ip6xh);
 427         len = ixhl - off;
 428
 429         while (len > 1) {
 430                 switch (xh[off]) {
 431                 case IPV6_TLV_PAD1:
 432                         optlen = 1;
 433                         break;
 434                 case IPV6_TLV_JUMBO:
 435                         optlen = xh[off + 1] + 2;
 436                         if (optlen != 6 || len < 6 || (off & 3) != 2)
 437                                 /* wrong jumbo option length/alignment */
 438                                 return 0;
 439                         *pl = ntohl(*(__be32 *)(xh + off + 2));
 440                         goto done;
 441                 default:
 442                         optlen = xh[off + 1] + 2;
 443                         if (optlen > len)
 444                                 /* ignore obscure options */
 445                                 goto done;
 446                         break;
 447                 }
 448                 off += optlen;
 449                 len -= optlen;
 450         }
 451
 452 done:
 453         return 1;
 454 }
 455
 456 static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
 457 {
 458         struct ipv6hdr *ip6h;
 459         struct ipv6_opt_hdr *ip6xh;
 460         unsigned int hl, ixhl;
 461         unsigned int pl;
 462         int ntkoff;
 463         u8 nexthdr;
 464
 465         ntkoff = skb_network_offset(skb);
 466
 467         hl = sizeof(*ip6h);
 468
 469         if (!pskb_may_pull(skb, hl + ntkoff))
 470                 goto fail;
 471
 472         ip6h = ipv6_hdr(skb);
 473
 474         pl = ntohs(ip6h->payload_len);
 475         nexthdr = ip6h->nexthdr;
 476
 477         do {
 478                 switch (nexthdr) {
 479                 case NEXTHDR_FRAGMENT:
 480                         goto ignore_skb;
 481                 case NEXTHDR_ROUTING:
 482                 case NEXTHDR_HOP:
 483                 case NEXTHDR_DEST:
 484                         if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
 485                                 goto fail;
 486                         ip6xh = (void *)(skb_network_header(skb) + hl);
 487                         ixhl = ipv6_optlen(ip6xh);
 488                         if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
 489                                 goto fail;
 490                         ip6xh = (void *)(skb_network_header(skb) + hl);
 491                         if ((nexthdr == NEXTHDR_HOP) &&
 492                             !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
 493                                 goto fail;
 494                         nexthdr = ip6xh->nexthdr;
 495                         hl += ixhl;
 496                         break;
 497                 case IPPROTO_ICMPV6:
 498                         if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
 499                                 if (!tcf_csum_ipv6_icmp(skb,
 500                                                         hl, pl + sizeof(*ip6h)))
 501                                         goto fail;
 502                         goto done;
 503                 case IPPROTO_TCP:
 504                         if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
 505                                 if (!tcf_csum_ipv6_tcp(skb,
 506                                                        hl, pl + sizeof(*ip6h)))
 507                                         goto fail;
 508                         goto done;
 509                 case IPPROTO_UDP:
 510                         if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
 511                                 if (!tcf_csum_ipv6_udp(skb, hl,
 512                                                        pl + sizeof(*ip6h), 0))
 513                                         goto fail;
 514                         goto done;
 515                 case IPPROTO_UDPLITE:
 516                         if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
 517                                 if (!tcf_csum_ipv6_udp(skb, hl,
 518                                                        pl + sizeof(*ip6h), 1))
 519                                         goto fail;
 520                         goto done;
 521                 case IPPROTO_SCTP:
 522                         if ((update_flags & TCA_CSUM_UPDATE_FLAG_SCTP) &&
 523                             !tcf_csum_sctp(skb, hl, pl + sizeof(*ip6h)))
 524                                 goto fail;
 525                         goto done;
 526                 default:
 527                         goto ignore_skb;
 528                 }
 529         } while (pskb_may_pull(skb, hl + 1 + ntkoff));
 530
 531 done:
 532 ignore_skb:
 533         return 1;
 534
 535 fail:
 536         return 0;
 537 }
 538
 539 static int tcf_csum(struct sk_buff *skb, const struct tc_action *a,
 540                     struct tcf_result *res)
 541 {
 542         struct tcf_csum *p = to_tcf_csum(a);
 543         int action;
 544         u32 update_flags;
 545
 546         spin_lock(&p->tcf_lock);
 547         tcf_lastuse_update(&p->tcf_tm);
 548         bstats_update(&p->tcf_bstats, skb);
 549         action = p->tcf_action;
 550         update_flags = p->update_flags;
 551         spin_unlock(&p->tcf_lock);
 552
 553         if (unlikely(action == TC_ACT_SHOT))
 554                 goto drop;
 555
 556         switch (tc_skb_protocol(skb)) {
 557         case cpu_to_be16(ETH_P_IP):
 558                 if (!tcf_csum_ipv4(skb, update_flags))
 559                         goto drop;
 560                 break;
 561         case cpu_to_be16(ETH_P_IPV6):
 562                 if (!tcf_csum_ipv6(skb, update_flags))
 563                         goto drop;
 564                 break;
 565         }
 566
 567         return action;
 568
 569 drop:
 570         spin_lock(&p->tcf_lock);
 571         p->tcf_qstats.drops++;
 572         spin_unlock(&p->tcf_lock);
 573         return TC_ACT_SHOT;
 574 }
 575
 576 static int tcf_csum_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 577                          int ref)
 578 {
 579         unsigned char *b = skb_tail_pointer(skb);
 580         struct tcf_csum *p = to_tcf_csum(a);
 581         struct tc_csum opt = {
 582                 .update_flags = p->update_flags,
 583                 .index   = p->tcf_index,
 584                 .action  = p->tcf_action,
 585                 .refcnt  = p->tcf_refcnt - ref,
 586                 .bindcnt = p->tcf_bindcnt - bind,
 587         };
 588         struct tcf_t t;
 589
 590         if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
 591                 goto nla_put_failure;
 592
 593         tcf_tm_dump(&t, &p->tcf_tm);
 594         if (nla_put_64bit(skb, TCA_CSUM_TM, sizeof(t), &t, TCA_CSUM_PAD))
 595                 goto nla_put_failure;
 596
 597         return skb->len;
 598
 599 nla_put_failure:
 600         nlmsg_trim(skb, b);
 601         return -1;
 602 }
 603
 604 static int tcf_csum_walker(struct net *net, struct sk_buff *skb,
 605                            struct netlink_callback *cb, int type,
 606                            const struct tc_action_ops *ops)
 607 {
 608         struct tc_action_net *tn = net_generic(net, csum_net_id);
 609
 610         return tcf_generic_walker(tn, skb, cb, type, ops);
 611 }
 612
 613 static int tcf_csum_search(struct net *net, struct tc_action **a, u32 index)
 614 {
 615         struct tc_action_net *tn = net_generic(net, csum_net_id);
 616
 617         return tcf_hash_search(tn, a, index);
 618 }
 619
 620 static struct tc_action_ops act_csum_ops = {
 621         .kind           = "csum",
 622         .type           = TCA_ACT_CSUM,
 623         .owner          = THIS_MODULE,
 624         .act            = tcf_csum,
 625         .dump           = tcf_csum_dump,
 626         .init           = tcf_csum_init,
 627         .walk           = tcf_csum_walker,
 628         .lookup         = tcf_csum_search,
 629         .size           = sizeof(struct tcf_csum),
 630 };
 631
 632 static __net_init int csum_init_net(struct net *net)
 633 {
 634         struct tc_action_net *tn = net_generic(net, csum_net_id);
 635
 636         return tc_action_net_init(tn, &act_csum_ops, CSUM_TAB_MASK);
 637 }
 638
 639 static void __net_exit csum_exit_net(struct net *net)
 640 {
 641         struct tc_action_net *tn = net_generic(net, csum_net_id);
 642
 643         tc_action_net_exit(tn);
 644 }
 645
 646 static struct pernet_operations csum_net_ops = {
 647         .init = csum_init_net,
 648         .exit = csum_exit_net,
 649         .id   = &csum_net_id,
 650         .size = sizeof(struct tc_action_net),
 651 };
 652
 653 MODULE_DESCRIPTION("Checksum updating actions");
 654 MODULE_LICENSE("GPL");
 655
 656 static int __init csum_init_module(void)
 657 {
 658         return tcf_register_action(&act_csum_ops, &csum_net_ops);
 659 }
 660
 661 static void __exit csum_cleanup_module(void)
 662 {
 663         tcf_unregister_action(&act_csum_ops, &csum_net_ops);
 664 }
 665
 666 module_init(csum_init_module);
 667 module_exit(csum_cleanup_module);