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