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