Pileus Git - ~andy/linux/blob - 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
  34 #include <net/act_api.h>
  35
  36 #include <linux/tc_act/tc_csum.h>
  37 #include <net/tc_act/tc_csum.h>
  38
  39 #define CSUM_TAB_MASK 15
  40 static u32 csum_idx_gen;
  41 static struct tcf_hashinfo csum_hash_info;
  42
  43 static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
  44         [TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
  45 };
  46
  47 static int tcf_csum_init(struct net *n, struct nlattr *nla, struct nlattr *est,
  48                          struct tc_action *a, int ovr, int bind)
  49 {
  50         struct nlattr *tb[TCA_CSUM_MAX + 1];
  51         struct tc_csum *parm;
  52         struct tcf_common *pc;
  53         struct tcf_csum *p;
  54         int ret = 0, err;
  55
  56         if (nla == NULL)
  57                 return -EINVAL;
  58
  59         err = nla_parse_nested(tb, TCA_CSUM_MAX, nla, csum_policy);
  60         if (err < 0)
  61                 return err;
  62
  63         if (tb[TCA_CSUM_PARMS] == NULL)
  64                 return -EINVAL;
  65         parm = nla_data(tb[TCA_CSUM_PARMS]);
  66
  67         pc = tcf_hash_check(parm->index, a, bind, &csum_hash_info);
  68         if (!pc) {
  69                 pc = tcf_hash_create(parm->index, est, a, sizeof(*p), bind,
  70                                      &csum_idx_gen, &csum_hash_info);
  71                 if (IS_ERR(pc))
  72                         return PTR_ERR(pc);
  73                 p = to_tcf_csum(pc);
  74                 ret = ACT_P_CREATED;
  75         } else {
  76                 p = to_tcf_csum(pc);
  77                 if (!ovr) {
  78                         tcf_hash_release(pc, bind, &csum_hash_info);
  79                         return -EEXIST;
  80                 }
  81         }
  82
  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_hash_insert(pc, &csum_hash_info);
  90
  91         return ret;
  92 }
  93
  94 static int tcf_csum_cleanup(struct tc_action *a, int bind)
  95 {
  96         struct tcf_csum *p = a->priv;
  97         return tcf_hash_release(&p->common, bind, &csum_hash_info);
  98 }
  99
 100 /**
 101  * tcf_csum_skb_nextlayer - Get next layer pointer
 102  * @skb: sk_buff to use
 103  * @ihl: previous summed headers length
 104  * @ipl: complete packet length
 105  * @jhl: next header length
 106  *
 107  * Check the expected next layer availability in the specified sk_buff.
 108  * Return the next layer pointer if pass, NULL otherwise.
 109  */
 110 static void *tcf_csum_skb_nextlayer(struct sk_buff *skb,
 111                                     unsigned int ihl, unsigned int ipl,
 112                                     unsigned int jhl)
 113 {
 114         int ntkoff = skb_network_offset(skb);
 115         int hl = ihl + jhl;
 116
 117         if (!pskb_may_pull(skb, ipl + ntkoff) || (ipl < hl) ||
 118             (skb_cloned(skb) &&
 119              !skb_clone_writable(skb, hl + ntkoff) &&
 120              pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
 121                 return NULL;
 122         else
 123                 return (void *)(skb_network_header(skb) + ihl);
 124 }
 125
 126 static int tcf_csum_ipv4_icmp(struct sk_buff *skb,
 127                               unsigned int ihl, unsigned int ipl)
 128 {
 129         struct icmphdr *icmph;
 130
 131         icmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmph));
 132         if (icmph == NULL)
 133                 return 0;
 134
 135         icmph->checksum = 0;
 136         skb->csum = csum_partial(icmph, ipl - ihl, 0);
 137         icmph->checksum = csum_fold(skb->csum);
 138
 139         skb->ip_summed = CHECKSUM_NONE;
 140
 141         return 1;
 142 }
 143
 144 static int tcf_csum_ipv4_igmp(struct sk_buff *skb,
 145                               unsigned int ihl, unsigned int ipl)
 146 {
 147         struct igmphdr *igmph;
 148
 149         igmph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*igmph));
 150         if (igmph == NULL)
 151                 return 0;
 152
 153         igmph->csum = 0;
 154         skb->csum = csum_partial(igmph, ipl - ihl, 0);
 155         igmph->csum = csum_fold(skb->csum);
 156
 157         skb->ip_summed = CHECKSUM_NONE;
 158
 159         return 1;
 160 }
 161
 162 static int tcf_csum_ipv6_icmp(struct sk_buff *skb,
 163                               unsigned int ihl, unsigned int ipl)
 164 {
 165         struct icmp6hdr *icmp6h;
 166         const struct ipv6hdr *ip6h;
 167
 168         icmp6h = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*icmp6h));
 169         if (icmp6h == NULL)
 170                 return 0;
 171
 172         ip6h = ipv6_hdr(skb);
 173         icmp6h->icmp6_cksum = 0;
 174         skb->csum = csum_partial(icmp6h, ipl - ihl, 0);
 175         icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr,
 176                                               ipl - ihl, IPPROTO_ICMPV6,
 177                                               skb->csum);
 178
 179         skb->ip_summed = CHECKSUM_NONE;
 180
 181         return 1;
 182 }
 183
 184 static int tcf_csum_ipv4_tcp(struct sk_buff *skb,
 185                              unsigned int ihl, unsigned int ipl)
 186 {
 187         struct tcphdr *tcph;
 188         const struct iphdr *iph;
 189
 190         tcph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*tcph));
 191         if (tcph == NULL)
 192                 return 0;
 193
 194         iph = ip_hdr(skb);
 195         tcph->check = 0;
 196         skb->csum = csum_partial(tcph, ipl - ihl, 0);
 197         tcph->check = tcp_v4_check(ipl - ihl,
 198                                    iph->saddr, iph->daddr, skb->csum);
 199
 200         skb->ip_summed = CHECKSUM_NONE;
 201
 202         return 1;
 203 }
 204
 205 static int tcf_csum_ipv6_tcp(struct sk_buff *skb,
 206                              unsigned int ihl, unsigned int ipl)
 207 {
 208         struct tcphdr *tcph;
 209         const struct ipv6hdr *ip6h;
 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,
 228                              unsigned int ihl, unsigned int ipl, int udplite)
 229 {
 230         struct udphdr *udph;
 231         const struct iphdr *iph;
 232         u16 ul;
 233
 234         /*
 235          * Support both UDP and UDPLITE checksum algorithms, Don't use
 236          * udph->len to get the real length without any protocol check,
 237          * UDPLITE uses udph->len for another thing,
 238          * Use iph->tot_len, or just ipl.
 239          */
 240
 241         udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
 242         if (udph == NULL)
 243                 return 0;
 244
 245         iph = ip_hdr(skb);
 246         ul = ntohs(udph->len);
 247
 248         if (udplite || udph->check) {
 249
 250                 udph->check = 0;
 251
 252                 if (udplite) {
 253                         if (ul == 0)
 254                                 skb->csum = csum_partial(udph, ipl - ihl, 0);
 255                         else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
 256                                 skb->csum = csum_partial(udph, ul, 0);
 257                         else
 258                                 goto ignore_obscure_skb;
 259                 } else {
 260                         if (ul != ipl - ihl)
 261                                 goto ignore_obscure_skb;
 262
 263                         skb->csum = csum_partial(udph, ul, 0);
 264                 }
 265
 266                 udph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
 267                                                 ul, iph->protocol,
 268                                                 skb->csum);
 269
 270                 if (!udph->check)
 271                         udph->check = CSUM_MANGLED_0;
 272         }
 273
 274         skb->ip_summed = CHECKSUM_NONE;
 275
 276 ignore_obscure_skb:
 277         return 1;
 278 }
 279
 280 static int tcf_csum_ipv6_udp(struct sk_buff *skb,
 281                              unsigned int ihl, unsigned int ipl, int udplite)
 282 {
 283         struct udphdr *udph;
 284         const struct ipv6hdr *ip6h;
 285         u16 ul;
 286
 287         /*
 288          * Support both UDP and UDPLITE checksum algorithms, Don't use
 289          * udph->len to get the real length without any protocol check,
 290          * UDPLITE uses udph->len for another thing,
 291          * Use ip6h->payload_len + sizeof(*ip6h) ... , or just ipl.
 292          */
 293
 294         udph = tcf_csum_skb_nextlayer(skb, ihl, ipl, sizeof(*udph));
 295         if (udph == NULL)
 296                 return 0;
 297
 298         ip6h = ipv6_hdr(skb);
 299         ul = ntohs(udph->len);
 300
 301         udph->check = 0;
 302
 303         if (udplite) {
 304                 if (ul == 0)
 305                         skb->csum = csum_partial(udph, ipl - ihl, 0);
 306
 307                 else if ((ul >= sizeof(*udph)) && (ul <= ipl - ihl))
 308                         skb->csum = csum_partial(udph, ul, 0);
 309
 310                 else
 311                         goto ignore_obscure_skb;
 312         } else {
 313                 if (ul != ipl - ihl)
 314                         goto ignore_obscure_skb;
 315
 316                 skb->csum = csum_partial(udph, ul, 0);
 317         }
 318
 319         udph->check = csum_ipv6_magic(&ip6h->saddr, &ip6h->daddr, ul,
 320                                       udplite ? IPPROTO_UDPLITE : IPPROTO_UDP,
 321                                       skb->csum);
 322
 323         if (!udph->check)
 324                 udph->check = CSUM_MANGLED_0;
 325
 326         skb->ip_summed = CHECKSUM_NONE;
 327
 328 ignore_obscure_skb:
 329         return 1;
 330 }
 331
 332 static int tcf_csum_ipv4(struct sk_buff *skb, u32 update_flags)
 333 {
 334         const struct iphdr *iph;
 335         int ntkoff;
 336
 337         ntkoff = skb_network_offset(skb);
 338
 339         if (!pskb_may_pull(skb, sizeof(*iph) + ntkoff))
 340                 goto fail;
 341
 342         iph = ip_hdr(skb);
 343
 344         switch (iph->frag_off & htons(IP_OFFSET) ? 0 : iph->protocol) {
 345         case IPPROTO_ICMP:
 346                 if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
 347                         if (!tcf_csum_ipv4_icmp(skb, iph->ihl * 4,
 348                                                 ntohs(iph->tot_len)))
 349                                 goto fail;
 350                 break;
 351         case IPPROTO_IGMP:
 352                 if (update_flags & TCA_CSUM_UPDATE_FLAG_IGMP)
 353                         if (!tcf_csum_ipv4_igmp(skb, iph->ihl * 4,
 354                                                 ntohs(iph->tot_len)))
 355                                 goto fail;
 356                 break;
 357         case IPPROTO_TCP:
 358                 if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
 359                         if (!tcf_csum_ipv4_tcp(skb, iph->ihl * 4,
 360                                                ntohs(iph->tot_len)))
 361                                 goto fail;
 362                 break;
 363         case IPPROTO_UDP:
 364                 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
 365                         if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
 366                                                ntohs(iph->tot_len), 0))
 367                                 goto fail;
 368                 break;
 369         case IPPROTO_UDPLITE:
 370                 if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
 371                         if (!tcf_csum_ipv4_udp(skb, iph->ihl * 4,
 372                                                ntohs(iph->tot_len), 1))
 373                                 goto fail;
 374                 break;
 375         }
 376
 377         if (update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
 378                 if (skb_cloned(skb) &&
 379                     !skb_clone_writable(skb, sizeof(*iph) + ntkoff) &&
 380                     pskb_expand_head(skb, 0, 0, GFP_ATOMIC))
 381                         goto fail;
 382
 383                 ip_send_check(ip_hdr(skb));
 384         }
 385
 386         return 1;
 387
 388 fail:
 389         return 0;
 390 }
 391
 392 static int tcf_csum_ipv6_hopopts(struct ipv6_opt_hdr *ip6xh,
 393                                  unsigned int ixhl, unsigned int *pl)
 394 {
 395         int off, len, optlen;
 396         unsigned char *xh = (void *)ip6xh;
 397
 398         off = sizeof(*ip6xh);
 399         len = ixhl - off;
 400
 401         while (len > 1) {
 402                 switch (xh[off]) {
 403                 case IPV6_TLV_PAD1:
 404                         optlen = 1;
 405                         break;
 406                 case IPV6_TLV_JUMBO:
 407                         optlen = xh[off + 1] + 2;
 408                         if (optlen != 6 || len < 6 || (off & 3) != 2)
 409                                 /* wrong jumbo option length/alignment */
 410                                 return 0;
 411                         *pl = ntohl(*(__be32 *)(xh + off + 2));
 412                         goto done;
 413                 default:
 414                         optlen = xh[off + 1] + 2;
 415                         if (optlen > len)
 416                                 /* ignore obscure options */
 417                                 goto done;
 418                         break;
 419                 }
 420                 off += optlen;
 421                 len -= optlen;
 422         }
 423
 424 done:
 425         return 1;
 426 }
 427
 428 static int tcf_csum_ipv6(struct sk_buff *skb, u32 update_flags)
 429 {
 430         struct ipv6hdr *ip6h;
 431         struct ipv6_opt_hdr *ip6xh;
 432         unsigned int hl, ixhl;
 433         unsigned int pl;
 434         int ntkoff;
 435         u8 nexthdr;
 436
 437         ntkoff = skb_network_offset(skb);
 438
 439         hl = sizeof(*ip6h);
 440
 441         if (!pskb_may_pull(skb, hl + ntkoff))
 442                 goto fail;
 443
 444         ip6h = ipv6_hdr(skb);
 445
 446         pl = ntohs(ip6h->payload_len);
 447         nexthdr = ip6h->nexthdr;
 448
 449         do {
 450                 switch (nexthdr) {
 451                 case NEXTHDR_FRAGMENT:
 452                         goto ignore_skb;
 453                 case NEXTHDR_ROUTING:
 454                 case NEXTHDR_HOP:
 455                 case NEXTHDR_DEST:
 456                         if (!pskb_may_pull(skb, hl + sizeof(*ip6xh) + ntkoff))
 457                                 goto fail;
 458                         ip6xh = (void *)(skb_network_header(skb) + hl);
 459                         ixhl = ipv6_optlen(ip6xh);
 460                         if (!pskb_may_pull(skb, hl + ixhl + ntkoff))
 461                                 goto fail;
 462                         ip6xh = (void *)(skb_network_header(skb) + hl);
 463                         if ((nexthdr == NEXTHDR_HOP) &&
 464                             !(tcf_csum_ipv6_hopopts(ip6xh, ixhl, &pl)))
 465                                 goto fail;
 466                         nexthdr = ip6xh->nexthdr;
 467                         hl += ixhl;
 468                         break;
 469                 case IPPROTO_ICMPV6:
 470                         if (update_flags & TCA_CSUM_UPDATE_FLAG_ICMP)
 471                                 if (!tcf_csum_ipv6_icmp(skb,
 472                                                         hl, pl + sizeof(*ip6h)))
 473                                         goto fail;
 474                         goto done;
 475                 case IPPROTO_TCP:
 476                         if (update_flags & TCA_CSUM_UPDATE_FLAG_TCP)
 477                                 if (!tcf_csum_ipv6_tcp(skb,
 478                                                        hl, pl + sizeof(*ip6h)))
 479                                         goto fail;
 480                         goto done;
 481                 case IPPROTO_UDP:
 482                         if (update_flags & TCA_CSUM_UPDATE_FLAG_UDP)
 483                                 if (!tcf_csum_ipv6_udp(skb, hl,
 484                                                        pl + sizeof(*ip6h), 0))
 485                                         goto fail;
 486                         goto done;
 487                 case IPPROTO_UDPLITE:
 488                         if (update_flags & TCA_CSUM_UPDATE_FLAG_UDPLITE)
 489                                 if (!tcf_csum_ipv6_udp(skb, hl,
 490                                                        pl + sizeof(*ip6h), 1))
 491                                         goto fail;
 492                         goto done;
 493                 default:
 494                         goto ignore_skb;
 495                 }
 496         } while (pskb_may_pull(skb, hl + 1 + ntkoff));
 497
 498 done:
 499 ignore_skb:
 500         return 1;
 501
 502 fail:
 503         return 0;
 504 }
 505
 506 static int tcf_csum(struct sk_buff *skb,
 507                     const struct tc_action *a, struct tcf_result *res)
 508 {
 509         struct tcf_csum *p = a->priv;
 510         int action;
 511         u32 update_flags;
 512
 513         spin_lock(&p->tcf_lock);
 514         p->tcf_tm.lastuse = jiffies;
 515         bstats_update(&p->tcf_bstats, skb);
 516         action = p->tcf_action;
 517         update_flags = p->update_flags;
 518         spin_unlock(&p->tcf_lock);
 519
 520         if (unlikely(action == TC_ACT_SHOT))
 521                 goto drop;
 522
 523         switch (skb->protocol) {
 524         case cpu_to_be16(ETH_P_IP):
 525                 if (!tcf_csum_ipv4(skb, update_flags))
 526                         goto drop;
 527                 break;
 528         case cpu_to_be16(ETH_P_IPV6):
 529                 if (!tcf_csum_ipv6(skb, update_flags))
 530                         goto drop;
 531                 break;
 532         }
 533
 534         return action;
 535
 536 drop:
 537         spin_lock(&p->tcf_lock);
 538         p->tcf_qstats.drops++;
 539         spin_unlock(&p->tcf_lock);
 540         return TC_ACT_SHOT;
 541 }
 542
 543 static int tcf_csum_dump(struct sk_buff *skb,
 544                          struct tc_action *a, int bind, int ref)
 545 {
 546         unsigned char *b = skb_tail_pointer(skb);
 547         struct tcf_csum *p = a->priv;
 548         struct tc_csum opt = {
 549                 .update_flags = p->update_flags,
 550                 .index   = p->tcf_index,
 551                 .action  = p->tcf_action,
 552                 .refcnt  = p->tcf_refcnt - ref,
 553                 .bindcnt = p->tcf_bindcnt - bind,
 554         };
 555         struct tcf_t t;
 556
 557         if (nla_put(skb, TCA_CSUM_PARMS, sizeof(opt), &opt))
 558                 goto nla_put_failure;
 559         t.install = jiffies_to_clock_t(jiffies - p->tcf_tm.install);
 560         t.lastuse = jiffies_to_clock_t(jiffies - p->tcf_tm.lastuse);
 561         t.expires = jiffies_to_clock_t(p->tcf_tm.expires);
 562         if (nla_put(skb, TCA_CSUM_TM, sizeof(t), &t))
 563                 goto nla_put_failure;
 564
 565         return skb->len;
 566
 567 nla_put_failure:
 568         nlmsg_trim(skb, b);
 569         return -1;
 570 }
 571
 572 static struct tc_action_ops act_csum_ops = {
 573         .kind           = "csum",
 574         .hinfo          = &csum_hash_info,
 575         .type           = TCA_ACT_CSUM,
 576         .capab          = TCA_CAP_NONE,
 577         .owner          = THIS_MODULE,
 578         .act            = tcf_csum,
 579         .dump           = tcf_csum_dump,
 580         .cleanup        = tcf_csum_cleanup,
 581         .init           = tcf_csum_init,
 582 };
 583
 584 MODULE_DESCRIPTION("Checksum updating actions");
 585 MODULE_LICENSE("GPL");
 586
 587 static int __init csum_init_module(void)
 588 {
 589         int err = tcf_hashinfo_init(&csum_hash_info, CSUM_TAB_MASK);
 590         if (err)
 591                 return err;
 592
 593         return tcf_register_action(&act_csum_ops);
 594 }
 595
 596 static void __exit csum_cleanup_module(void)
 597 {
 598         tcf_unregister_action(&act_csum_ops);
 599 }
 600
 601 module_init(csum_init_module);
 602 module_exit(csum_cleanup_module);