net/sched/act_ife.c

   1 /*
   2  * net/sched/ife.c      Inter-FE action based on ForCES WG InterFE LFB
   3  *
   4  *              Refer to:
   5  *              draft-ietf-forces-interfelfb-03
   6  *              and
   7  *              netdev01 paper:
   8  *              "Distributing Linux Traffic Control Classifier-Action
   9  *              Subsystem"
  10  *              Authors: Jamal Hadi Salim and Damascene M. Joachimpillai
  11  *
  12  *              This program is free software; you can redistribute it and/or
  13  *              modify it under the terms of the GNU General Public License
  14  *              as published by the Free Software Foundation; either version
  15  *              2 of the License, or (at your option) any later version.
  16  *
  17  * copyright Jamal Hadi Salim (2015)
  18  *
  19 */
  20
  21 #include <linux/types.h>
  22 #include <linux/kernel.h>
  23 #include <linux/string.h>
  24 #include <linux/errno.h>
  25 #include <linux/skbuff.h>
  26 #include <linux/rtnetlink.h>
  27 #include <linux/module.h>
  28 #include <linux/init.h>
  29 #include <net/net_namespace.h>
  30 #include <net/netlink.h>
  31 #include <net/pkt_sched.h>
  32 #include <uapi/linux/tc_act/tc_ife.h>
  33 #include <net/tc_act/tc_ife.h>
  34 #include <linux/etherdevice.h>
  35
  36 #define IFE_TAB_MASK 15
  37
  38 static int ife_net_id;
  39 static int max_metacnt = IFE_META_MAX + 1;
  40
  41 static const struct nla_policy ife_policy[TCA_IFE_MAX + 1] = {
  42         [TCA_IFE_PARMS] = { .len = sizeof(struct tc_ife)},
  43         [TCA_IFE_DMAC] = { .len = ETH_ALEN},
  44         [TCA_IFE_SMAC] = { .len = ETH_ALEN},
  45         [TCA_IFE_TYPE] = { .type = NLA_U16},
  46 };
  47
  48 /* Caller takes care of presenting data in network order
  49 */
  50 int ife_tlv_meta_encode(void *skbdata, u16 attrtype, u16 dlen, const void *dval)
  51 {
  52         u32 *tlv = (u32 *)(skbdata);
  53         u16 totlen = nla_total_size(dlen);      /*alignment + hdr */
  54         char *dptr = (char *)tlv + NLA_HDRLEN;
  55         u32 htlv = attrtype << 16 | totlen;
  56
  57         *tlv = htonl(htlv);
  58         memset(dptr, 0, totlen - NLA_HDRLEN);
  59         memcpy(dptr, dval, dlen);
  60
  61         return totlen;
  62 }
  63 EXPORT_SYMBOL_GPL(ife_tlv_meta_encode);
  64
  65 int ife_get_meta_u32(struct sk_buff *skb, struct tcf_meta_info *mi)
  66 {
  67         if (mi->metaval)
  68                 return nla_put_u32(skb, mi->metaid, *(u32 *)mi->metaval);
  69         else
  70                 return nla_put(skb, mi->metaid, 0, NULL);
  71 }
  72 EXPORT_SYMBOL_GPL(ife_get_meta_u32);
  73
  74 int ife_check_meta_u32(u32 metaval, struct tcf_meta_info *mi)
  75 {
  76         if (metaval || mi->metaval)
  77                 return 8; /* T+L+V == 2+2+4 */
  78
  79         return 0;
  80 }
  81 EXPORT_SYMBOL_GPL(ife_check_meta_u32);
  82
  83 int ife_encode_meta_u32(u32 metaval, void *skbdata, struct tcf_meta_info *mi)
  84 {
  85         u32 edata = metaval;
  86
  87         if (mi->metaval)
  88                 edata = *(u32 *)mi->metaval;
  89         else if (metaval)
  90                 edata = metaval;
  91
  92         if (!edata) /* will not encode */
  93                 return 0;
  94
  95         edata = htonl(edata);
  96         return ife_tlv_meta_encode(skbdata, mi->metaid, 4, &edata);
  97 }
  98 EXPORT_SYMBOL_GPL(ife_encode_meta_u32);
  99
 100 int ife_get_meta_u16(struct sk_buff *skb, struct tcf_meta_info *mi)
 101 {
 102         if (mi->metaval)
 103                 return nla_put_u16(skb, mi->metaid, *(u16 *)mi->metaval);
 104         else
 105                 return nla_put(skb, mi->metaid, 0, NULL);
 106 }
 107 EXPORT_SYMBOL_GPL(ife_get_meta_u16);
 108
 109 int ife_alloc_meta_u32(struct tcf_meta_info *mi, void *metaval, gfp_t gfp)
 110 {
 111         mi->metaval = kmemdup(metaval, sizeof(u32), gfp);
 112         if (!mi->metaval)
 113                 return -ENOMEM;
 114
 115         return 0;
 116 }
 117 EXPORT_SYMBOL_GPL(ife_alloc_meta_u32);
 118
 119 int ife_alloc_meta_u16(struct tcf_meta_info *mi, void *metaval, gfp_t gfp)
 120 {
 121         mi->metaval = kmemdup(metaval, sizeof(u16), gfp);
 122         if (!mi->metaval)
 123                 return -ENOMEM;
 124
 125         return 0;
 126 }
 127 EXPORT_SYMBOL_GPL(ife_alloc_meta_u16);
 128
 129 void ife_release_meta_gen(struct tcf_meta_info *mi)
 130 {
 131         kfree(mi->metaval);
 132 }
 133 EXPORT_SYMBOL_GPL(ife_release_meta_gen);
 134
 135 int ife_validate_meta_u32(void *val, int len)
 136 {
 137         if (len == 4)
 138                 return 0;
 139
 140         return -EINVAL;
 141 }
 142 EXPORT_SYMBOL_GPL(ife_validate_meta_u32);
 143
 144 int ife_validate_meta_u16(void *val, int len)
 145 {
 146         /* length will include padding */
 147         if (len == NLA_ALIGN(2))
 148                 return 0;
 149
 150         return -EINVAL;
 151 }
 152 EXPORT_SYMBOL_GPL(ife_validate_meta_u16);
 153
 154 static LIST_HEAD(ifeoplist);
 155 static DEFINE_RWLOCK(ife_mod_lock);
 156
 157 static struct tcf_meta_ops *find_ife_oplist(u16 metaid)
 158 {
 159         struct tcf_meta_ops *o;
 160
 161         read_lock(&ife_mod_lock);
 162         list_for_each_entry(o, &ifeoplist, list) {
 163                 if (o->metaid == metaid) {
 164                         if (!try_module_get(o->owner))
 165                                 o = NULL;
 166                         read_unlock(&ife_mod_lock);
 167                         return o;
 168                 }
 169         }
 170         read_unlock(&ife_mod_lock);
 171
 172         return NULL;
 173 }
 174
 175 int register_ife_op(struct tcf_meta_ops *mops)
 176 {
 177         struct tcf_meta_ops *m;
 178
 179         if (!mops->metaid || !mops->metatype || !mops->name ||
 180             !mops->check_presence || !mops->encode || !mops->decode ||
 181             !mops->get || !mops->alloc)
 182                 return -EINVAL;
 183
 184         write_lock(&ife_mod_lock);
 185
 186         list_for_each_entry(m, &ifeoplist, list) {
 187                 if (m->metaid == mops->metaid ||
 188                     (strcmp(mops->name, m->name) == 0)) {
 189                         write_unlock(&ife_mod_lock);
 190                         return -EEXIST;
 191                 }
 192         }
 193
 194         if (!mops->release)
 195                 mops->release = ife_release_meta_gen;
 196
 197         list_add_tail(&mops->list, &ifeoplist);
 198         write_unlock(&ife_mod_lock);
 199         return 0;
 200 }
 201 EXPORT_SYMBOL_GPL(unregister_ife_op);
 202
 203 int unregister_ife_op(struct tcf_meta_ops *mops)
 204 {
 205         struct tcf_meta_ops *m;
 206         int err = -ENOENT;
 207
 208         write_lock(&ife_mod_lock);
 209         list_for_each_entry(m, &ifeoplist, list) {
 210                 if (m->metaid == mops->metaid) {
 211                         list_del(&mops->list);
 212                         err = 0;
 213                         break;
 214                 }
 215         }
 216         write_unlock(&ife_mod_lock);
 217
 218         return err;
 219 }
 220 EXPORT_SYMBOL_GPL(register_ife_op);
 221
 222 static int ife_validate_metatype(struct tcf_meta_ops *ops, void *val, int len)
 223 {
 224         int ret = 0;
 225         /* XXX: unfortunately cant use nla_policy at this point
 226         * because a length of 0 is valid in the case of
 227         * "allow". "use" semantics do enforce for proper
 228         * length and i couldve use nla_policy but it makes it hard
 229         * to use it just for that..
 230         */
 231         if (ops->validate)
 232                 return ops->validate(val, len);
 233
 234         if (ops->metatype == NLA_U32)
 235                 ret = ife_validate_meta_u32(val, len);
 236         else if (ops->metatype == NLA_U16)
 237                 ret = ife_validate_meta_u16(val, len);
 238
 239         return ret;
 240 }
 241
 242 /* called when adding new meta information
 243  * under ife->tcf_lock for existing action
 244 */
 245 static int load_metaops_and_vet(struct tcf_ife_info *ife, u32 metaid,
 246                                 void *val, int len, bool exists)
 247 {
 248         struct tcf_meta_ops *ops = find_ife_oplist(metaid);
 249         int ret = 0;
 250
 251         if (!ops) {
 252                 ret = -ENOENT;
 253 #ifdef CONFIG_MODULES
 254                 if (exists)
 255                         spin_unlock_bh(&ife->tcf_lock);
 256                 rtnl_unlock();
 257                 request_module("ifemeta%u", metaid);
 258                 rtnl_lock();
 259                 if (exists)
 260                         spin_lock_bh(&ife->tcf_lock);
 261                 ops = find_ife_oplist(metaid);
 262 #endif
 263         }
 264
 265         if (ops) {
 266                 ret = 0;
 267                 if (len)
 268                         ret = ife_validate_metatype(ops, val, len);
 269
 270                 module_put(ops->owner);
 271         }
 272
 273         return ret;
 274 }
 275
 276 /* called when adding new meta information
 277  * under ife->tcf_lock for existing action
 278 */
 279 static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval,
 280                         int len, bool atomic)
 281 {
 282         struct tcf_meta_info *mi = NULL;
 283         struct tcf_meta_ops *ops = find_ife_oplist(metaid);
 284         int ret = 0;
 285
 286         if (!ops)
 287                 return -ENOENT;
 288
 289         mi = kzalloc(sizeof(*mi), atomic ? GFP_ATOMIC : GFP_KERNEL);
 290         if (!mi) {
 291                 /*put back what find_ife_oplist took */
 292                 module_put(ops->owner);
 293                 return -ENOMEM;
 294         }
 295
 296         mi->metaid = metaid;
 297         mi->ops = ops;
 298         if (len > 0) {
 299                 ret = ops->alloc(mi, metaval, atomic ? GFP_ATOMIC : GFP_KERNEL);
 300                 if (ret != 0) {
 301                         kfree(mi);
 302                         module_put(ops->owner);
 303                         return ret;
 304                 }
 305         }
 306
 307         list_add_tail(&mi->metalist, &ife->metalist);
 308
 309         return ret;
 310 }
 311
 312 static int use_all_metadata(struct tcf_ife_info *ife)
 313 {
 314         struct tcf_meta_ops *o;
 315         int rc = 0;
 316         int installed = 0;
 317
 318         read_lock(&ife_mod_lock);
 319         list_for_each_entry(o, &ifeoplist, list) {
 320                 rc = add_metainfo(ife, o->metaid, NULL, 0, true);
 321                 if (rc == 0)
 322                         installed += 1;
 323         }
 324         read_unlock(&ife_mod_lock);
 325
 326         if (installed)
 327                 return 0;
 328         else
 329                 return -EINVAL;
 330 }
 331
 332 static int dump_metalist(struct sk_buff *skb, struct tcf_ife_info *ife)
 333 {
 334         struct tcf_meta_info *e;
 335         struct nlattr *nest;
 336         unsigned char *b = skb_tail_pointer(skb);
 337         int total_encoded = 0;
 338
 339         /*can only happen on decode */
 340         if (list_empty(&ife->metalist))
 341                 return 0;
 342
 343         nest = nla_nest_start(skb, TCA_IFE_METALST);
 344         if (!nest)
 345                 goto out_nlmsg_trim;
 346
 347         list_for_each_entry(e, &ife->metalist, metalist) {
 348                 if (!e->ops->get(skb, e))
 349                         total_encoded += 1;
 350         }
 351
 352         if (!total_encoded)
 353                 goto out_nlmsg_trim;
 354
 355         nla_nest_end(skb, nest);
 356
 357         return 0;
 358
 359 out_nlmsg_trim:
 360         nlmsg_trim(skb, b);
 361         return -1;
 362 }
 363
 364 /* under ife->tcf_lock */
 365 static void _tcf_ife_cleanup(struct tc_action *a, int bind)
 366 {
 367         struct tcf_ife_info *ife = a->priv;
 368         struct tcf_meta_info *e, *n;
 369
 370         list_for_each_entry_safe(e, n, &ife->metalist, metalist) {
 371                 module_put(e->ops->owner);
 372                 list_del(&e->metalist);
 373                 if (e->metaval) {
 374                         if (e->ops->release)
 375                                 e->ops->release(e);
 376                         else
 377                                 kfree(e->metaval);
 378                 }
 379                 kfree(e);
 380         }
 381 }
 382
 383 static void tcf_ife_cleanup(struct tc_action *a, int bind)
 384 {
 385         struct tcf_ife_info *ife = a->priv;
 386
 387         spin_lock_bh(&ife->tcf_lock);
 388         _tcf_ife_cleanup(a, bind);
 389         spin_unlock_bh(&ife->tcf_lock);
 390 }
 391
 392 /* under ife->tcf_lock for existing action */
 393 static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb,
 394                              bool exists)
 395 {
 396         int len = 0;
 397         int rc = 0;
 398         int i = 0;
 399         void *val;
 400
 401         for (i = 1; i < max_metacnt; i++) {
 402                 if (tb[i]) {
 403                         val = nla_data(tb[i]);
 404                         len = nla_len(tb[i]);
 405
 406                         rc = load_metaops_and_vet(ife, i, val, len, exists);
 407                         if (rc != 0)
 408                                 return rc;
 409
 410                         rc = add_metainfo(ife, i, val, len, exists);
 411                         if (rc)
 412                                 return rc;
 413                 }
 414         }
 415
 416         return rc;
 417 }
 418
 419 static int tcf_ife_init(struct net *net, struct nlattr *nla,
 420                         struct nlattr *est, struct tc_action *a,
 421                         int ovr, int bind)
 422 {
 423         struct tc_action_net *tn = net_generic(net, ife_net_id);
 424         struct nlattr *tb[TCA_IFE_MAX + 1];
 425         struct nlattr *tb2[IFE_META_MAX + 1];
 426         struct tcf_ife_info *ife;
 427         struct tc_ife *parm;
 428         u16 ife_type = 0;
 429         u8 *daddr = NULL;
 430         u8 *saddr = NULL;
 431         int ret = 0, exists = 0;
 432         int err;
 433
 434         err = nla_parse_nested(tb, TCA_IFE_MAX, nla, ife_policy);
 435         if (err < 0)
 436                 return err;
 437
 438         if (!tb[TCA_IFE_PARMS])
 439                 return -EINVAL;
 440
 441         parm = nla_data(tb[TCA_IFE_PARMS]);
 442
 443         exists = tcf_hash_check(tn, parm->index, a, bind);
 444         if (exists && bind)
 445                 return 0;
 446
 447         if (parm->flags & IFE_ENCODE) {
 448                 /* Until we get issued the ethertype, we cant have
 449                  * a default..
 450                 **/
 451                 if (!tb[TCA_IFE_TYPE]) {
 452                         if (exists)
 453                                 tcf_hash_release(a, bind);
 454                         pr_info("You MUST pass etherype for encoding\n");
 455                         return -EINVAL;
 456                 }
 457         }
 458
 459         if (!exists) {
 460                 ret = tcf_hash_create(tn, parm->index, est, a, sizeof(*ife),
 461                                       bind, false);
 462                 if (ret)
 463                         return ret;
 464                 ret = ACT_P_CREATED;
 465         } else {
 466                 tcf_hash_release(a, bind);
 467                 if (!ovr)
 468                         return -EEXIST;
 469         }
 470
 471         ife = to_ife(a);
 472         ife->flags = parm->flags;
 473
 474         if (parm->flags & IFE_ENCODE) {
 475                 ife_type = nla_get_u16(tb[TCA_IFE_TYPE]);
 476                 if (tb[TCA_IFE_DMAC])
 477                         daddr = nla_data(tb[TCA_IFE_DMAC]);
 478                 if (tb[TCA_IFE_SMAC])
 479                         saddr = nla_data(tb[TCA_IFE_SMAC]);
 480         }
 481
 482         if (exists)
 483                 spin_lock_bh(&ife->tcf_lock);
 484         ife->tcf_action = parm->action;
 485
 486         if (parm->flags & IFE_ENCODE) {
 487                 if (daddr)
 488                         ether_addr_copy(ife->eth_dst, daddr);
 489                 else
 490                         eth_zero_addr(ife->eth_dst);
 491
 492                 if (saddr)
 493                         ether_addr_copy(ife->eth_src, saddr);
 494                 else
 495                         eth_zero_addr(ife->eth_src);
 496
 497                 ife->eth_type = ife_type;
 498         }
 499
 500         if (ret == ACT_P_CREATED)
 501                 INIT_LIST_HEAD(&ife->metalist);
 502
 503         if (tb[TCA_IFE_METALST]) {
 504                 err = nla_parse_nested(tb2, IFE_META_MAX, tb[TCA_IFE_METALST],
 505                                        NULL);
 506                 if (err) {
 507 metadata_parse_err:
 508                         if (exists)
 509                                 tcf_hash_release(a, bind);
 510                         if (ret == ACT_P_CREATED)
 511                                 _tcf_ife_cleanup(a, bind);
 512
 513                         if (exists)
 514                                 spin_unlock_bh(&ife->tcf_lock);
 515                         return err;
 516                 }
 517
 518                 err = populate_metalist(ife, tb2, exists);
 519                 if (err)
 520                         goto metadata_parse_err;
 521
 522         } else {
 523                 /* if no passed metadata allow list or passed allow-all
 524                  * then here we process by adding as many supported metadatum
 525                  * as we can. You better have at least one else we are
 526                  * going to bail out
 527                  */
 528                 err = use_all_metadata(ife);
 529                 if (err) {
 530                         if (ret == ACT_P_CREATED)
 531                                 _tcf_ife_cleanup(a, bind);
 532
 533                         if (exists)
 534                                 spin_unlock_bh(&ife->tcf_lock);
 535                         return err;
 536                 }
 537         }
 538
 539         if (exists)
 540                 spin_unlock_bh(&ife->tcf_lock);
 541
 542         if (ret == ACT_P_CREATED)
 543                 tcf_hash_insert(tn, a);
 544
 545         return ret;
 546 }
 547
 548 static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 549                         int ref)
 550 {
 551         unsigned char *b = skb_tail_pointer(skb);
 552         struct tcf_ife_info *ife = a->priv;
 553         struct tc_ife opt = {
 554                 .index = ife->tcf_index,
 555                 .refcnt = ife->tcf_refcnt - ref,
 556                 .bindcnt = ife->tcf_bindcnt - bind,
 557                 .action = ife->tcf_action,
 558                 .flags = ife->flags,
 559         };
 560         struct tcf_t t;
 561
 562         if (nla_put(skb, TCA_IFE_PARMS, sizeof(opt), &opt))
 563                 goto nla_put_failure;
 564
 565         t.install = jiffies_to_clock_t(jiffies - ife->tcf_tm.install);
 566         t.lastuse = jiffies_to_clock_t(jiffies - ife->tcf_tm.lastuse);
 567         t.expires = jiffies_to_clock_t(ife->tcf_tm.expires);
 568         if (nla_put_64bit(skb, TCA_IFE_TM, sizeof(t), &t, TCA_IFE_PAD))
 569                 goto nla_put_failure;
 570
 571         if (!is_zero_ether_addr(ife->eth_dst)) {
 572                 if (nla_put(skb, TCA_IFE_DMAC, ETH_ALEN, ife->eth_dst))
 573                         goto nla_put_failure;
 574         }
 575
 576         if (!is_zero_ether_addr(ife->eth_src)) {
 577                 if (nla_put(skb, TCA_IFE_SMAC, ETH_ALEN, ife->eth_src))
 578                         goto nla_put_failure;
 579         }
 580
 581         if (nla_put(skb, TCA_IFE_TYPE, 2, &ife->eth_type))
 582                 goto nla_put_failure;
 583
 584         if (dump_metalist(skb, ife)) {
 585                 /*ignore failure to dump metalist */
 586                 pr_info("Failed to dump metalist\n");
 587         }
 588
 589         return skb->len;
 590
 591 nla_put_failure:
 592         nlmsg_trim(skb, b);
 593         return -1;
 594 }
 595
 596 int find_decode_metaid(struct sk_buff *skb, struct tcf_ife_info *ife,
 597                        u16 metaid, u16 mlen, void *mdata)
 598 {
 599         struct tcf_meta_info *e;
 600
 601         /* XXX: use hash to speed up */
 602         list_for_each_entry(e, &ife->metalist, metalist) {
 603                 if (metaid == e->metaid) {
 604                         if (e->ops) {
 605                                 /* We check for decode presence already */
 606                                 return e->ops->decode(skb, mdata, mlen);
 607                         }
 608                 }
 609         }
 610
 611         return 0;
 612 }
 613
 614 struct ifeheadr {
 615         __be16 metalen;
 616         u8 tlv_data[];
 617 };
 618
 619 struct meta_tlvhdr {
 620         __be16 type;
 621         __be16 len;
 622 };
 623
 624 static int tcf_ife_decode(struct sk_buff *skb, const struct tc_action *a,
 625                           struct tcf_result *res)
 626 {
 627         struct tcf_ife_info *ife = a->priv;
 628         int action = ife->tcf_action;
 629         struct ifeheadr *ifehdr = (struct ifeheadr *)skb->data;
 630         u16 ifehdrln = ifehdr->metalen;
 631         struct meta_tlvhdr *tlv = (struct meta_tlvhdr *)(ifehdr->tlv_data);
 632
 633         spin_lock(&ife->tcf_lock);
 634         bstats_update(&ife->tcf_bstats, skb);
 635         ife->tcf_tm.lastuse = jiffies;
 636         spin_unlock(&ife->tcf_lock);
 637
 638         ifehdrln = ntohs(ifehdrln);
 639         if (unlikely(!pskb_may_pull(skb, ifehdrln))) {
 640                 spin_lock(&ife->tcf_lock);
 641                 ife->tcf_qstats.drops++;
 642                 spin_unlock(&ife->tcf_lock);
 643                 return TC_ACT_SHOT;
 644         }
 645
 646         skb_set_mac_header(skb, ifehdrln);
 647         __skb_pull(skb, ifehdrln);
 648         skb->protocol = eth_type_trans(skb, skb->dev);
 649         ifehdrln -= IFE_METAHDRLEN;
 650
 651         while (ifehdrln > 0) {
 652                 u8 *tlvdata = (u8 *)tlv;
 653                 u16 mtype = tlv->type;
 654                 u16 mlen = tlv->len;
 655
 656                 mtype = ntohs(mtype);
 657                 mlen = ntohs(mlen);
 658
 659                 if (find_decode_metaid(skb, ife, mtype, (mlen - 4),
 660                                        (void *)(tlvdata + 4))) {
 661                         /* abuse overlimits to count when we receive metadata
 662                          * but dont have an ops for it
 663                          */
 664                         pr_info_ratelimited("Unknown metaid %d alnlen %d\n",
 665                                             mtype, mlen);
 666                         ife->tcf_qstats.overlimits++;
 667                 }
 668
 669                 tlvdata += mlen;
 670                 ifehdrln -= mlen;
 671                 tlv = (struct meta_tlvhdr *)tlvdata;
 672         }
 673
 674         skb_reset_network_header(skb);
 675         return action;
 676 }
 677
 678 /*XXX: check if we can do this at install time instead of current
 679  * send data path
 680 **/
 681 static int ife_get_sz(struct sk_buff *skb, struct tcf_ife_info *ife)
 682 {
 683         struct tcf_meta_info *e, *n;
 684         int tot_run_sz = 0, run_sz = 0;
 685
 686         list_for_each_entry_safe(e, n, &ife->metalist, metalist) {
 687                 if (e->ops->check_presence) {
 688                         run_sz = e->ops->check_presence(skb, e);
 689                         tot_run_sz += run_sz;
 690                 }
 691         }
 692
 693         return tot_run_sz;
 694 }
 695
 696 static int tcf_ife_encode(struct sk_buff *skb, const struct tc_action *a,
 697                           struct tcf_result *res)
 698 {
 699         struct tcf_ife_info *ife = a->priv;
 700         int action = ife->tcf_action;
 701         struct ethhdr *oethh;   /* outer ether header */
 702         struct ethhdr *iethh;   /* inner eth header */
 703         struct tcf_meta_info *e;
 704         /*
 705            OUTERHDR:TOTMETALEN:{TLVHDR:Metadatum:TLVHDR..}:ORIGDATA
 706            where ORIGDATA = original ethernet header ...
 707          */
 708         u16 metalen = ife_get_sz(skb, ife);
 709         int hdrm = metalen + skb->dev->hard_header_len + IFE_METAHDRLEN;
 710         unsigned int skboff = skb->dev->hard_header_len;
 711         u32 at = G_TC_AT(skb->tc_verd);
 712         int new_len = skb->len + hdrm;
 713         bool exceed_mtu = false;
 714         int err;
 715
 716         if (at & AT_EGRESS) {
 717                 if (new_len > skb->dev->mtu)
 718                         exceed_mtu = true;
 719         }
 720
 721         spin_lock(&ife->tcf_lock);
 722         bstats_update(&ife->tcf_bstats, skb);
 723         ife->tcf_tm.lastuse = jiffies;
 724
 725         if (!metalen) {         /* no metadata to send */
 726                 /* abuse overlimits to count when we allow packet
 727                  * with no metadata
 728                  */
 729                 ife->tcf_qstats.overlimits++;
 730                 spin_unlock(&ife->tcf_lock);
 731                 return action;
 732         }
 733         /* could be stupid policy setup or mtu config
 734          * so lets be conservative.. */
 735         if ((action == TC_ACT_SHOT) || exceed_mtu) {
 736                 ife->tcf_qstats.drops++;
 737                 spin_unlock(&ife->tcf_lock);
 738                 return TC_ACT_SHOT;
 739         }
 740
 741         iethh = eth_hdr(skb);
 742
 743         err = skb_cow_head(skb, hdrm);
 744         if (unlikely(err)) {
 745                 ife->tcf_qstats.drops++;
 746                 spin_unlock(&ife->tcf_lock);
 747                 return TC_ACT_SHOT;
 748         }
 749
 750         if (!(at & AT_EGRESS))
 751                 skb_push(skb, skb->dev->hard_header_len);
 752
 753         __skb_push(skb, hdrm);
 754         memcpy(skb->data, iethh, skb->mac_len);
 755         skb_reset_mac_header(skb);
 756         oethh = eth_hdr(skb);
 757
 758         /*total metadata length */
 759         metalen += IFE_METAHDRLEN;
 760         metalen = htons(metalen);
 761         memcpy((skb->data + skboff), &metalen, IFE_METAHDRLEN);
 762         skboff += IFE_METAHDRLEN;
 763
 764         /* XXX: we dont have a clever way of telling encode to
 765          * not repeat some of the computations that are done by
 766          * ops->presence_check...
 767          */
 768         list_for_each_entry(e, &ife->metalist, metalist) {
 769                 if (e->ops->encode) {
 770                         err = e->ops->encode(skb, (void *)(skb->data + skboff),
 771                                              e);
 772                 }
 773                 if (err < 0) {
 774                         /* too corrupt to keep around if overwritten */
 775                         ife->tcf_qstats.drops++;
 776                         spin_unlock(&ife->tcf_lock);
 777                         return TC_ACT_SHOT;
 778                 }
 779                 skboff += err;
 780         }
 781
 782         if (!is_zero_ether_addr(ife->eth_src))
 783                 ether_addr_copy(oethh->h_source, ife->eth_src);
 784         else
 785                 ether_addr_copy(oethh->h_source, iethh->h_source);
 786         if (!is_zero_ether_addr(ife->eth_dst))
 787                 ether_addr_copy(oethh->h_dest, ife->eth_dst);
 788         else
 789                 ether_addr_copy(oethh->h_dest, iethh->h_dest);
 790         oethh->h_proto = htons(ife->eth_type);
 791
 792         if (!(at & AT_EGRESS))
 793                 skb_pull(skb, skb->dev->hard_header_len);
 794
 795         spin_unlock(&ife->tcf_lock);
 796
 797         return action;
 798 }
 799
 800 static int tcf_ife_act(struct sk_buff *skb, const struct tc_action *a,
 801                        struct tcf_result *res)
 802 {
 803         struct tcf_ife_info *ife = a->priv;
 804
 805         if (ife->flags & IFE_ENCODE)
 806                 return tcf_ife_encode(skb, a, res);
 807
 808         if (!(ife->flags & IFE_ENCODE))
 809                 return tcf_ife_decode(skb, a, res);
 810
 811         pr_info_ratelimited("unknown failure(policy neither de/encode\n");
 812         spin_lock(&ife->tcf_lock);
 813         bstats_update(&ife->tcf_bstats, skb);
 814         ife->tcf_tm.lastuse = jiffies;
 815         ife->tcf_qstats.drops++;
 816         spin_unlock(&ife->tcf_lock);
 817
 818         return TC_ACT_SHOT;
 819 }
 820
 821 static int tcf_ife_walker(struct net *net, struct sk_buff *skb,
 822                           struct netlink_callback *cb, int type,
 823                           struct tc_action *a)
 824 {
 825         struct tc_action_net *tn = net_generic(net, ife_net_id);
 826
 827         return tcf_generic_walker(tn, skb, cb, type, a);
 828 }
 829
 830 static int tcf_ife_search(struct net *net, struct tc_action *a, u32 index)
 831 {
 832         struct tc_action_net *tn = net_generic(net, ife_net_id);
 833
 834         return tcf_hash_search(tn, a, index);
 835 }
 836
 837 static struct tc_action_ops act_ife_ops = {
 838         .kind = "ife",
 839         .type = TCA_ACT_IFE,
 840         .owner = THIS_MODULE,
 841         .act = tcf_ife_act,
 842         .dump = tcf_ife_dump,
 843         .cleanup = tcf_ife_cleanup,
 844         .init = tcf_ife_init,
 845         .walk = tcf_ife_walker,
 846         .lookup = tcf_ife_search,
 847 };
 848
 849 static __net_init int ife_init_net(struct net *net)
 850 {
 851         struct tc_action_net *tn = net_generic(net, ife_net_id);
 852
 853         return tc_action_net_init(tn, &act_ife_ops, IFE_TAB_MASK);
 854 }
 855
 856 static void __net_exit ife_exit_net(struct net *net)
 857 {
 858         struct tc_action_net *tn = net_generic(net, ife_net_id);
 859
 860         tc_action_net_exit(tn);
 861 }
 862
 863 static struct pernet_operations ife_net_ops = {
 864         .init = ife_init_net,
 865         .exit = ife_exit_net,
 866         .id   = &ife_net_id,
 867         .size = sizeof(struct tc_action_net),
 868 };
 869
 870 static int __init ife_init_module(void)
 871 {
 872         return tcf_register_action(&act_ife_ops, &ife_net_ops);
 873 }
 874
 875 static void __exit ife_cleanup_module(void)
 876 {
 877         tcf_unregister_action(&act_ife_ops, &ife_net_ops);
 878 }
 879
 880 module_init(ife_init_module);
 881 module_exit(ife_cleanup_module);
 882
 883 MODULE_AUTHOR("Jamal Hadi Salim(2015)");
 884 MODULE_DESCRIPTION("Inter-FE LFB action");
 885 MODULE_LICENSE("GPL");