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 #include <net/ife.h>
  36
  37 static unsigned int ife_net_id;
  38 static int max_metacnt = IFE_META_MAX + 1;
  39 static struct tc_action_ops act_ife_ops;
  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 int ife_encode_meta_u16(u16 metaval, void *skbdata, struct tcf_meta_info *mi)
  49 {
  50         u16 edata = 0;
  51
  52         if (mi->metaval)
  53                 edata = *(u16 *)mi->metaval;
  54         else if (metaval)
  55                 edata = metaval;
  56
  57         if (!edata) /* will not encode */
  58                 return 0;
  59
  60         edata = htons(edata);
  61         return ife_tlv_meta_encode(skbdata, mi->metaid, 2, &edata);
  62 }
  63 EXPORT_SYMBOL_GPL(ife_encode_meta_u16);
  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_check_meta_u16(u16 metaval, struct tcf_meta_info *mi)
  84 {
  85         if (metaval || mi->metaval)
  86                 return 8; /* T+L+(V) == 2+2+(2+2bytepad) */
  87
  88         return 0;
  89 }
  90 EXPORT_SYMBOL_GPL(ife_check_meta_u16);
  91
  92 int ife_encode_meta_u32(u32 metaval, void *skbdata, struct tcf_meta_info *mi)
  93 {
  94         u32 edata = metaval;
  95
  96         if (mi->metaval)
  97                 edata = *(u32 *)mi->metaval;
  98         else if (metaval)
  99                 edata = metaval;
 100
 101         if (!edata) /* will not encode */
 102                 return 0;
 103
 104         edata = htonl(edata);
 105         return ife_tlv_meta_encode(skbdata, mi->metaid, 4, &edata);
 106 }
 107 EXPORT_SYMBOL_GPL(ife_encode_meta_u32);
 108
 109 int ife_get_meta_u16(struct sk_buff *skb, struct tcf_meta_info *mi)
 110 {
 111         if (mi->metaval)
 112                 return nla_put_u16(skb, mi->metaid, *(u16 *)mi->metaval);
 113         else
 114                 return nla_put(skb, mi->metaid, 0, NULL);
 115 }
 116 EXPORT_SYMBOL_GPL(ife_get_meta_u16);
 117
 118 int ife_alloc_meta_u32(struct tcf_meta_info *mi, void *metaval, gfp_t gfp)
 119 {
 120         mi->metaval = kmemdup(metaval, sizeof(u32), gfp);
 121         if (!mi->metaval)
 122                 return -ENOMEM;
 123
 124         return 0;
 125 }
 126 EXPORT_SYMBOL_GPL(ife_alloc_meta_u32);
 127
 128 int ife_alloc_meta_u16(struct tcf_meta_info *mi, void *metaval, gfp_t gfp)
 129 {
 130         mi->metaval = kmemdup(metaval, sizeof(u16), gfp);
 131         if (!mi->metaval)
 132                 return -ENOMEM;
 133
 134         return 0;
 135 }
 136 EXPORT_SYMBOL_GPL(ife_alloc_meta_u16);
 137
 138 void ife_release_meta_gen(struct tcf_meta_info *mi)
 139 {
 140         kfree(mi->metaval);
 141 }
 142 EXPORT_SYMBOL_GPL(ife_release_meta_gen);
 143
 144 int ife_validate_meta_u32(void *val, int len)
 145 {
 146         if (len == sizeof(u32))
 147                 return 0;
 148
 149         return -EINVAL;
 150 }
 151 EXPORT_SYMBOL_GPL(ife_validate_meta_u32);
 152
 153 int ife_validate_meta_u16(void *val, int len)
 154 {
 155         /* length will not include padding */
 156         if (len == sizeof(u16))
 157                 return 0;
 158
 159         return -EINVAL;
 160 }
 161 EXPORT_SYMBOL_GPL(ife_validate_meta_u16);
 162
 163 static LIST_HEAD(ifeoplist);
 164 static DEFINE_RWLOCK(ife_mod_lock);
 165
 166 static struct tcf_meta_ops *find_ife_oplist(u16 metaid)
 167 {
 168         struct tcf_meta_ops *o;
 169
 170         read_lock(&ife_mod_lock);
 171         list_for_each_entry(o, &ifeoplist, list) {
 172                 if (o->metaid == metaid) {
 173                         if (!try_module_get(o->owner))
 174                                 o = NULL;
 175                         read_unlock(&ife_mod_lock);
 176                         return o;
 177                 }
 178         }
 179         read_unlock(&ife_mod_lock);
 180
 181         return NULL;
 182 }
 183
 184 int register_ife_op(struct tcf_meta_ops *mops)
 185 {
 186         struct tcf_meta_ops *m;
 187
 188         if (!mops->metaid || !mops->metatype || !mops->name ||
 189             !mops->check_presence || !mops->encode || !mops->decode ||
 190             !mops->get || !mops->alloc)
 191                 return -EINVAL;
 192
 193         write_lock(&ife_mod_lock);
 194
 195         list_for_each_entry(m, &ifeoplist, list) {
 196                 if (m->metaid == mops->metaid ||
 197                     (strcmp(mops->name, m->name) == 0)) {
 198                         write_unlock(&ife_mod_lock);
 199                         return -EEXIST;
 200                 }
 201         }
 202
 203         if (!mops->release)
 204                 mops->release = ife_release_meta_gen;
 205
 206         list_add_tail(&mops->list, &ifeoplist);
 207         write_unlock(&ife_mod_lock);
 208         return 0;
 209 }
 210 EXPORT_SYMBOL_GPL(unregister_ife_op);
 211
 212 int unregister_ife_op(struct tcf_meta_ops *mops)
 213 {
 214         struct tcf_meta_ops *m;
 215         int err = -ENOENT;
 216
 217         write_lock(&ife_mod_lock);
 218         list_for_each_entry(m, &ifeoplist, list) {
 219                 if (m->metaid == mops->metaid) {
 220                         list_del(&mops->list);
 221                         err = 0;
 222                         break;
 223                 }
 224         }
 225         write_unlock(&ife_mod_lock);
 226
 227         return err;
 228 }
 229 EXPORT_SYMBOL_GPL(register_ife_op);
 230
 231 static int ife_validate_metatype(struct tcf_meta_ops *ops, void *val, int len)
 232 {
 233         int ret = 0;
 234         /* XXX: unfortunately cant use nla_policy at this point
 235         * because a length of 0 is valid in the case of
 236         * "allow". "use" semantics do enforce for proper
 237         * length and i couldve use nla_policy but it makes it hard
 238         * to use it just for that..
 239         */
 240         if (ops->validate)
 241                 return ops->validate(val, len);
 242
 243         if (ops->metatype == NLA_U32)
 244                 ret = ife_validate_meta_u32(val, len);
 245         else if (ops->metatype == NLA_U16)
 246                 ret = ife_validate_meta_u16(val, len);
 247
 248         return ret;
 249 }
 250
 251 /* called when adding new meta information
 252  * under ife->tcf_lock for existing action
 253 */
 254 static int load_metaops_and_vet(struct tcf_ife_info *ife, u32 metaid,
 255                                 void *val, int len, bool exists)
 256 {
 257         struct tcf_meta_ops *ops = find_ife_oplist(metaid);
 258         int ret = 0;
 259
 260         if (!ops) {
 261                 ret = -ENOENT;
 262 #ifdef CONFIG_MODULES
 263                 if (exists)
 264                         spin_unlock_bh(&ife->tcf_lock);
 265                 rtnl_unlock();
 266                 request_module("ifemeta%u", metaid);
 267                 rtnl_lock();
 268                 if (exists)
 269                         spin_lock_bh(&ife->tcf_lock);
 270                 ops = find_ife_oplist(metaid);
 271 #endif
 272         }
 273
 274         if (ops) {
 275                 ret = 0;
 276                 if (len)
 277                         ret = ife_validate_metatype(ops, val, len);
 278
 279                 module_put(ops->owner);
 280         }
 281
 282         return ret;
 283 }
 284
 285 /* called when adding new meta information
 286  * under ife->tcf_lock for existing action
 287 */
 288 static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval,
 289                         int len, bool atomic)
 290 {
 291         struct tcf_meta_info *mi = NULL;
 292         struct tcf_meta_ops *ops = find_ife_oplist(metaid);
 293         int ret = 0;
 294
 295         if (!ops)
 296                 return -ENOENT;
 297
 298         mi = kzalloc(sizeof(*mi), atomic ? GFP_ATOMIC : GFP_KERNEL);
 299         if (!mi) {
 300                 /*put back what find_ife_oplist took */
 301                 module_put(ops->owner);
 302                 return -ENOMEM;
 303         }
 304
 305         mi->metaid = metaid;
 306         mi->ops = ops;
 307         if (len > 0) {
 308                 ret = ops->alloc(mi, metaval, atomic ? GFP_ATOMIC : GFP_KERNEL);
 309                 if (ret != 0) {
 310                         kfree(mi);
 311                         module_put(ops->owner);
 312                         return ret;
 313                 }
 314         }
 315
 316         list_add_tail(&mi->metalist, &ife->metalist);
 317
 318         return ret;
 319 }
 320
 321 static int use_all_metadata(struct tcf_ife_info *ife)
 322 {
 323         struct tcf_meta_ops *o;
 324         int rc = 0;
 325         int installed = 0;
 326
 327         read_lock(&ife_mod_lock);
 328         list_for_each_entry(o, &ifeoplist, list) {
 329                 rc = add_metainfo(ife, o->metaid, NULL, 0, true);
 330                 if (rc == 0)
 331                         installed += 1;
 332         }
 333         read_unlock(&ife_mod_lock);
 334
 335         if (installed)
 336                 return 0;
 337         else
 338                 return -EINVAL;
 339 }
 340
 341 static int dump_metalist(struct sk_buff *skb, struct tcf_ife_info *ife)
 342 {
 343         struct tcf_meta_info *e;
 344         struct nlattr *nest;
 345         unsigned char *b = skb_tail_pointer(skb);
 346         int total_encoded = 0;
 347
 348         /*can only happen on decode */
 349         if (list_empty(&ife->metalist))
 350                 return 0;
 351
 352         nest = nla_nest_start(skb, TCA_IFE_METALST);
 353         if (!nest)
 354                 goto out_nlmsg_trim;
 355
 356         list_for_each_entry(e, &ife->metalist, metalist) {
 357                 if (!e->ops->get(skb, e))
 358                         total_encoded += 1;
 359         }
 360
 361         if (!total_encoded)
 362                 goto out_nlmsg_trim;
 363
 364         nla_nest_end(skb, nest);
 365
 366         return 0;
 367
 368 out_nlmsg_trim:
 369         nlmsg_trim(skb, b);
 370         return -1;
 371 }
 372
 373 /* under ife->tcf_lock */
 374 static void _tcf_ife_cleanup(struct tc_action *a, int bind)
 375 {
 376         struct tcf_ife_info *ife = to_ife(a);
 377         struct tcf_meta_info *e, *n;
 378
 379         list_for_each_entry_safe(e, n, &ife->metalist, metalist) {
 380                 module_put(e->ops->owner);
 381                 list_del(&e->metalist);
 382                 if (e->metaval) {
 383                         if (e->ops->release)
 384                                 e->ops->release(e);
 385                         else
 386                                 kfree(e->metaval);
 387                 }
 388                 kfree(e);
 389         }
 390 }
 391
 392 static void tcf_ife_cleanup(struct tc_action *a, int bind)
 393 {
 394         struct tcf_ife_info *ife = to_ife(a);
 395
 396         spin_lock_bh(&ife->tcf_lock);
 397         _tcf_ife_cleanup(a, bind);
 398         spin_unlock_bh(&ife->tcf_lock);
 399 }
 400
 401 /* under ife->tcf_lock for existing action */
 402 static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb,
 403                              bool exists)
 404 {
 405         int len = 0;
 406         int rc = 0;
 407         int i = 0;
 408         void *val;
 409
 410         for (i = 1; i < max_metacnt; i++) {
 411                 if (tb[i]) {
 412                         val = nla_data(tb[i]);
 413                         len = nla_len(tb[i]);
 414
 415                         rc = load_metaops_and_vet(ife, i, val, len, exists);
 416                         if (rc != 0)
 417                                 return rc;
 418
 419                         rc = add_metainfo(ife, i, val, len, exists);
 420                         if (rc)
 421                                 return rc;
 422                 }
 423         }
 424
 425         return rc;
 426 }
 427
 428 static int tcf_ife_init(struct net *net, struct nlattr *nla,
 429                         struct nlattr *est, struct tc_action **a,
 430                         int ovr, int bind)
 431 {
 432         struct tc_action_net *tn = net_generic(net, ife_net_id);
 433         struct nlattr *tb[TCA_IFE_MAX + 1];
 434         struct nlattr *tb2[IFE_META_MAX + 1];
 435         struct tcf_ife_info *ife;
 436         u16 ife_type = ETH_P_IFE;
 437         struct tc_ife *parm;
 438         u8 *daddr = NULL;
 439         u8 *saddr = NULL;
 440         bool exists = false;
 441         int ret = 0;
 442         int err;
 443
 444         err = nla_parse_nested(tb, TCA_IFE_MAX, nla, ife_policy, NULL);
 445         if (err < 0)
 446                 return err;
 447
 448         if (!tb[TCA_IFE_PARMS])
 449                 return -EINVAL;
 450
 451         parm = nla_data(tb[TCA_IFE_PARMS]);
 452
 453         exists = tcf_idr_check(tn, parm->index, a, bind);
 454         if (exists && bind)
 455                 return 0;
 456
 457         if (!exists) {
 458                 ret = tcf_idr_create(tn, parm->index, est, a, &act_ife_ops,
 459                                      bind, false);
 460                 if (ret)
 461                         return ret;
 462                 ret = ACT_P_CREATED;
 463         } else {
 464                 tcf_idr_release(*a, bind);
 465                 if (!ovr)
 466                         return -EEXIST;
 467         }
 468
 469         ife = to_ife(*a);
 470         ife->flags = parm->flags;
 471
 472         if (parm->flags & IFE_ENCODE) {
 473                 if (tb[TCA_IFE_TYPE])
 474                         ife_type = nla_get_u16(tb[TCA_IFE_TYPE]);
 475                 if (tb[TCA_IFE_DMAC])
 476                         daddr = nla_data(tb[TCA_IFE_DMAC]);
 477                 if (tb[TCA_IFE_SMAC])
 478                         saddr = nla_data(tb[TCA_IFE_SMAC]);
 479         }
 480
 481         if (exists)
 482                 spin_lock_bh(&ife->tcf_lock);
 483         ife->tcf_action = parm->action;
 484
 485         if (parm->flags & IFE_ENCODE) {
 486                 if (daddr)
 487                         ether_addr_copy(ife->eth_dst, daddr);
 488                 else
 489                         eth_zero_addr(ife->eth_dst);
 490
 491                 if (saddr)
 492                         ether_addr_copy(ife->eth_src, saddr);
 493                 else
 494                         eth_zero_addr(ife->eth_src);
 495
 496                 ife->eth_type = ife_type;
 497         }
 498
 499         if (ret == ACT_P_CREATED)
 500                 INIT_LIST_HEAD(&ife->metalist);
 501
 502         if (tb[TCA_IFE_METALST]) {
 503                 err = nla_parse_nested(tb2, IFE_META_MAX, tb[TCA_IFE_METALST],
 504                                        NULL, NULL);
 505                 if (err) {
 506 metadata_parse_err:
 507                         if (exists)
 508                                 tcf_idr_release(*a, bind);
 509                         if (ret == ACT_P_CREATED)
 510                                 _tcf_ife_cleanup(*a, bind);
 511
 512                         if (exists)
 513                                 spin_unlock_bh(&ife->tcf_lock);
 514                         return err;
 515                 }
 516
 517                 err = populate_metalist(ife, tb2, exists);
 518                 if (err)
 519                         goto metadata_parse_err;
 520
 521         } else {
 522                 /* if no passed metadata allow list or passed allow-all
 523                  * then here we process by adding as many supported metadatum
 524                  * as we can. You better have at least one else we are
 525                  * going to bail out
 526                  */
 527                 err = use_all_metadata(ife);
 528                 if (err) {
 529                         if (ret == ACT_P_CREATED)
 530                                 _tcf_ife_cleanup(*a, bind);
 531
 532                         if (exists)
 533                                 spin_unlock_bh(&ife->tcf_lock);
 534                         return err;
 535                 }
 536         }
 537
 538         if (exists)
 539                 spin_unlock_bh(&ife->tcf_lock);
 540
 541         if (ret == ACT_P_CREATED)
 542                 tcf_idr_insert(tn, *a);
 543
 544         return ret;
 545 }
 546
 547 static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 548                         int ref)
 549 {
 550         unsigned char *b = skb_tail_pointer(skb);
 551         struct tcf_ife_info *ife = to_ife(a);
 552         struct tc_ife opt = {
 553                 .index = ife->tcf_index,
 554                 .refcnt = ife->tcf_refcnt - ref,
 555                 .bindcnt = ife->tcf_bindcnt - bind,
 556                 .action = ife->tcf_action,
 557                 .flags = ife->flags,
 558         };
 559         struct tcf_t t;
 560
 561         if (nla_put(skb, TCA_IFE_PARMS, sizeof(opt), &opt))
 562                 goto nla_put_failure;
 563
 564         tcf_tm_dump(&t, &ife->tcf_tm);
 565         if (nla_put_64bit(skb, TCA_IFE_TM, sizeof(t), &t, TCA_IFE_PAD))
 566                 goto nla_put_failure;
 567
 568         if (!is_zero_ether_addr(ife->eth_dst)) {
 569                 if (nla_put(skb, TCA_IFE_DMAC, ETH_ALEN, ife->eth_dst))
 570                         goto nla_put_failure;
 571         }
 572
 573         if (!is_zero_ether_addr(ife->eth_src)) {
 574                 if (nla_put(skb, TCA_IFE_SMAC, ETH_ALEN, ife->eth_src))
 575                         goto nla_put_failure;
 576         }
 577
 578         if (nla_put(skb, TCA_IFE_TYPE, 2, &ife->eth_type))
 579                 goto nla_put_failure;
 580
 581         if (dump_metalist(skb, ife)) {
 582                 /*ignore failure to dump metalist */
 583                 pr_info("Failed to dump metalist\n");
 584         }
 585
 586         return skb->len;
 587
 588 nla_put_failure:
 589         nlmsg_trim(skb, b);
 590         return -1;
 591 }
 592
 593 static int find_decode_metaid(struct sk_buff *skb, struct tcf_ife_info *ife,
 594                               u16 metaid, u16 mlen, void *mdata)
 595 {
 596         struct tcf_meta_info *e;
 597
 598         /* XXX: use hash to speed up */
 599         list_for_each_entry(e, &ife->metalist, metalist) {
 600                 if (metaid == e->metaid) {
 601                         if (e->ops) {
 602                                 /* We check for decode presence already */
 603                                 return e->ops->decode(skb, mdata, mlen);
 604                         }
 605                 }
 606         }
 607
 608         return 0;
 609 }
 610
 611 static int tcf_ife_decode(struct sk_buff *skb, const struct tc_action *a,
 612                           struct tcf_result *res)
 613 {
 614         struct tcf_ife_info *ife = to_ife(a);
 615         int action = ife->tcf_action;
 616         u8 *ifehdr_end;
 617         u8 *tlv_data;
 618         u16 metalen;
 619
 620         spin_lock(&ife->tcf_lock);
 621         bstats_update(&ife->tcf_bstats, skb);
 622         tcf_lastuse_update(&ife->tcf_tm);
 623         spin_unlock(&ife->tcf_lock);
 624
 625         if (skb_at_tc_ingress(skb))
 626                 skb_push(skb, skb->dev->hard_header_len);
 627
 628         tlv_data = ife_decode(skb, &metalen);
 629         if (unlikely(!tlv_data)) {
 630                 spin_lock(&ife->tcf_lock);
 631                 ife->tcf_qstats.drops++;
 632                 spin_unlock(&ife->tcf_lock);
 633                 return TC_ACT_SHOT;
 634         }
 635
 636         ifehdr_end = tlv_data + metalen;
 637         for (; tlv_data < ifehdr_end; tlv_data = ife_tlv_meta_next(tlv_data)) {
 638                 u8 *curr_data;
 639                 u16 mtype;
 640                 u16 dlen;
 641
 642                 curr_data = ife_tlv_meta_decode(tlv_data, &mtype, &dlen, NULL);
 643
 644                 if (find_decode_metaid(skb, ife, mtype, dlen, curr_data)) {
 645                         /* abuse overlimits to count when we receive metadata
 646                          * but dont have an ops for it
 647                          */
 648                         pr_info_ratelimited("Unknown metaid %d dlen %d\n",
 649                                             mtype, dlen);
 650                         ife->tcf_qstats.overlimits++;
 651                 }
 652         }
 653
 654         if (WARN_ON(tlv_data != ifehdr_end)) {
 655                 spin_lock(&ife->tcf_lock);
 656                 ife->tcf_qstats.drops++;
 657                 spin_unlock(&ife->tcf_lock);
 658                 return TC_ACT_SHOT;
 659         }
 660
 661         skb->protocol = eth_type_trans(skb, skb->dev);
 662         skb_reset_network_header(skb);
 663
 664         return action;
 665 }
 666
 667 /*XXX: check if we can do this at install time instead of current
 668  * send data path
 669 **/
 670 static int ife_get_sz(struct sk_buff *skb, struct tcf_ife_info *ife)
 671 {
 672         struct tcf_meta_info *e, *n;
 673         int tot_run_sz = 0, run_sz = 0;
 674
 675         list_for_each_entry_safe(e, n, &ife->metalist, metalist) {
 676                 if (e->ops->check_presence) {
 677                         run_sz = e->ops->check_presence(skb, e);
 678                         tot_run_sz += run_sz;
 679                 }
 680         }
 681
 682         return tot_run_sz;
 683 }
 684
 685 static int tcf_ife_encode(struct sk_buff *skb, const struct tc_action *a,
 686                           struct tcf_result *res)
 687 {
 688         struct tcf_ife_info *ife = to_ife(a);
 689         int action = ife->tcf_action;
 690         struct ethhdr *oethh;   /* outer ether header */
 691         struct tcf_meta_info *e;
 692         /*
 693            OUTERHDR:TOTMETALEN:{TLVHDR:Metadatum:TLVHDR..}:ORIGDATA
 694            where ORIGDATA = original ethernet header ...
 695          */
 696         u16 metalen = ife_get_sz(skb, ife);
 697         int hdrm = metalen + skb->dev->hard_header_len + IFE_METAHDRLEN;
 698         unsigned int skboff = 0;
 699         int new_len = skb->len + hdrm;
 700         bool exceed_mtu = false;
 701         void *ife_meta;
 702         int err = 0;
 703
 704         if (!skb_at_tc_ingress(skb)) {
 705                 if (new_len > skb->dev->mtu)
 706                         exceed_mtu = true;
 707         }
 708
 709         spin_lock(&ife->tcf_lock);
 710         bstats_update(&ife->tcf_bstats, skb);
 711         tcf_lastuse_update(&ife->tcf_tm);
 712
 713         if (!metalen) {         /* no metadata to send */
 714                 /* abuse overlimits to count when we allow packet
 715                  * with no metadata
 716                  */
 717                 ife->tcf_qstats.overlimits++;
 718                 spin_unlock(&ife->tcf_lock);
 719                 return action;
 720         }
 721         /* could be stupid policy setup or mtu config
 722          * so lets be conservative.. */
 723         if ((action == TC_ACT_SHOT) || exceed_mtu) {
 724                 ife->tcf_qstats.drops++;
 725                 spin_unlock(&ife->tcf_lock);
 726                 return TC_ACT_SHOT;
 727         }
 728
 729         if (skb_at_tc_ingress(skb))
 730                 skb_push(skb, skb->dev->hard_header_len);
 731
 732         ife_meta = ife_encode(skb, metalen);
 733
 734         /* XXX: we dont have a clever way of telling encode to
 735          * not repeat some of the computations that are done by
 736          * ops->presence_check...
 737          */
 738         list_for_each_entry(e, &ife->metalist, metalist) {
 739                 if (e->ops->encode) {
 740                         err = e->ops->encode(skb, (void *)(ife_meta + skboff),
 741                                              e);
 742                 }
 743                 if (err < 0) {
 744                         /* too corrupt to keep around if overwritten */
 745                         ife->tcf_qstats.drops++;
 746                         spin_unlock(&ife->tcf_lock);
 747                         return TC_ACT_SHOT;
 748                 }
 749                 skboff += err;
 750         }
 751         oethh = (struct ethhdr *)skb->data;
 752
 753         if (!is_zero_ether_addr(ife->eth_src))
 754                 ether_addr_copy(oethh->h_source, ife->eth_src);
 755         if (!is_zero_ether_addr(ife->eth_dst))
 756                 ether_addr_copy(oethh->h_dest, ife->eth_dst);
 757         oethh->h_proto = htons(ife->eth_type);
 758
 759         if (skb_at_tc_ingress(skb))
 760                 skb_pull(skb, skb->dev->hard_header_len);
 761
 762         spin_unlock(&ife->tcf_lock);
 763
 764         return action;
 765 }
 766
 767 static int tcf_ife_act(struct sk_buff *skb, const struct tc_action *a,
 768                        struct tcf_result *res)
 769 {
 770         struct tcf_ife_info *ife = to_ife(a);
 771
 772         if (ife->flags & IFE_ENCODE)
 773                 return tcf_ife_encode(skb, a, res);
 774
 775         if (!(ife->flags & IFE_ENCODE))
 776                 return tcf_ife_decode(skb, a, res);
 777
 778         pr_info_ratelimited("unknown failure(policy neither de/encode\n");
 779         spin_lock(&ife->tcf_lock);
 780         bstats_update(&ife->tcf_bstats, skb);
 781         tcf_lastuse_update(&ife->tcf_tm);
 782         ife->tcf_qstats.drops++;
 783         spin_unlock(&ife->tcf_lock);
 784
 785         return TC_ACT_SHOT;
 786 }
 787
 788 static int tcf_ife_walker(struct net *net, struct sk_buff *skb,
 789                           struct netlink_callback *cb, int type,
 790                           const struct tc_action_ops *ops)
 791 {
 792         struct tc_action_net *tn = net_generic(net, ife_net_id);
 793
 794         return tcf_generic_walker(tn, skb, cb, type, ops);
 795 }
 796
 797 static int tcf_ife_search(struct net *net, struct tc_action **a, u32 index)
 798 {
 799         struct tc_action_net *tn = net_generic(net, ife_net_id);
 800
 801         return tcf_idr_search(tn, a, index);
 802 }
 803
 804 static struct tc_action_ops act_ife_ops = {
 805         .kind = "ife",
 806         .type = TCA_ACT_IFE,
 807         .owner = THIS_MODULE,
 808         .act = tcf_ife_act,
 809         .dump = tcf_ife_dump,
 810         .cleanup = tcf_ife_cleanup,
 811         .init = tcf_ife_init,
 812         .walk = tcf_ife_walker,
 813         .lookup = tcf_ife_search,
 814         .size = sizeof(struct tcf_ife_info),
 815 };
 816
 817 static __net_init int ife_init_net(struct net *net)
 818 {
 819         struct tc_action_net *tn = net_generic(net, ife_net_id);
 820
 821         return tc_action_net_init(tn, &act_ife_ops);
 822 }
 823
 824 static void __net_exit ife_exit_net(struct net *net)
 825 {
 826         struct tc_action_net *tn = net_generic(net, ife_net_id);
 827
 828         tc_action_net_exit(tn);
 829 }
 830
 831 static struct pernet_operations ife_net_ops = {
 832         .init = ife_init_net,
 833         .exit = ife_exit_net,
 834         .id   = &ife_net_id,
 835         .size = sizeof(struct tc_action_net),
 836 };
 837
 838 static int __init ife_init_module(void)
 839 {
 840         return tcf_register_action(&act_ife_ops, &ife_net_ops);
 841 }
 842
 843 static void __exit ife_cleanup_module(void)
 844 {
 845         tcf_unregister_action(&act_ife_ops, &ife_net_ops);
 846 }
 847
 848 module_init(ife_init_module);
 849 module_exit(ife_cleanup_module);
 850
 851 MODULE_AUTHOR("Jamal Hadi Salim(2015)");
 852 MODULE_DESCRIPTION("Inter-FE LFB action");
 853 MODULE_LICENSE("GPL");