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