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)
 110 {
 111         mi->metaval = kmemdup(metaval, sizeof(u32), GFP_KERNEL);
 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)
 120 {
 121         mi->metaval = kmemdup(metaval, sizeof(u16), GFP_KERNEL);
 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
 244 */
 245 static int load_metaops_and_vet(struct tcf_ife_info *ife, u32 metaid,
 246                                 void *val, int len)
 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                 spin_unlock_bh(&ife->tcf_lock);
 255                 rtnl_unlock();
 256                 request_module("ifemeta%u", metaid);
 257                 rtnl_lock();
 258                 spin_lock_bh(&ife->tcf_lock);
 259                 ops = find_ife_oplist(metaid);
 260 #endif
 261         }
 262
 263         if (ops) {
 264                 ret = 0;
 265                 if (len)
 266                         ret = ife_validate_metatype(ops, val, len);
 267
 268                 module_put(ops->owner);
 269         }
 270
 271         return ret;
 272 }
 273
 274 /* called when adding new meta information
 275  * under ife->tcf_lock
 276 */
 277 static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval,
 278                         int len)
 279 {
 280         struct tcf_meta_info *mi = NULL;
 281         struct tcf_meta_ops *ops = find_ife_oplist(metaid);
 282         int ret = 0;
 283
 284         if (!ops)
 285                 return -ENOENT;
 286
 287         mi = kzalloc(sizeof(*mi), GFP_KERNEL);
 288         if (!mi) {
 289                 /*put back what find_ife_oplist took */
 290                 module_put(ops->owner);
 291                 return -ENOMEM;
 292         }
 293
 294         mi->metaid = metaid;
 295         mi->ops = ops;
 296         if (len > 0) {
 297                 ret = ops->alloc(mi, metaval);
 298                 if (ret != 0) {
 299                         kfree(mi);
 300                         module_put(ops->owner);
 301                         return ret;
 302                 }
 303         }
 304
 305         list_add_tail(&mi->metalist, &ife->metalist);
 306
 307         return ret;
 308 }
 309
 310 static int use_all_metadata(struct tcf_ife_info *ife)
 311 {
 312         struct tcf_meta_ops *o;
 313         int rc = 0;
 314         int installed = 0;
 315
 316         list_for_each_entry(o, &ifeoplist, list) {
 317                 rc = add_metainfo(ife, o->metaid, NULL, 0);
 318                 if (rc == 0)
 319                         installed += 1;
 320         }
 321
 322         if (installed)
 323                 return 0;
 324         else
 325                 return -EINVAL;
 326 }
 327
 328 static int dump_metalist(struct sk_buff *skb, struct tcf_ife_info *ife)
 329 {
 330         struct tcf_meta_info *e;
 331         struct nlattr *nest;
 332         unsigned char *b = skb_tail_pointer(skb);
 333         int total_encoded = 0;
 334
 335         /*can only happen on decode */
 336         if (list_empty(&ife->metalist))
 337                 return 0;
 338
 339         nest = nla_nest_start(skb, TCA_IFE_METALST);
 340         if (!nest)
 341                 goto out_nlmsg_trim;
 342
 343         list_for_each_entry(e, &ife->metalist, metalist) {
 344                 if (!e->ops->get(skb, e))
 345                         total_encoded += 1;
 346         }
 347
 348         if (!total_encoded)
 349                 goto out_nlmsg_trim;
 350
 351         nla_nest_end(skb, nest);
 352
 353         return 0;
 354
 355 out_nlmsg_trim:
 356         nlmsg_trim(skb, b);
 357         return -1;
 358 }
 359
 360 /* under ife->tcf_lock */
 361 static void _tcf_ife_cleanup(struct tc_action *a, int bind)
 362 {
 363         struct tcf_ife_info *ife = a->priv;
 364         struct tcf_meta_info *e, *n;
 365
 366         list_for_each_entry_safe(e, n, &ife->metalist, metalist) {
 367                 module_put(e->ops->owner);
 368                 list_del(&e->metalist);
 369                 if (e->metaval) {
 370                         if (e->ops->release)
 371                                 e->ops->release(e);
 372                         else
 373                                 kfree(e->metaval);
 374                 }
 375                 kfree(e);
 376         }
 377 }
 378
 379 static void tcf_ife_cleanup(struct tc_action *a, int bind)
 380 {
 381         struct tcf_ife_info *ife = a->priv;
 382
 383         spin_lock_bh(&ife->tcf_lock);
 384         _tcf_ife_cleanup(a, bind);
 385         spin_unlock_bh(&ife->tcf_lock);
 386 }
 387
 388 /* under ife->tcf_lock */
 389 static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb)
 390 {
 391         int len = 0;
 392         int rc = 0;
 393         int i = 0;
 394         void *val;
 395
 396         for (i = 1; i < max_metacnt; i++) {
 397                 if (tb[i]) {
 398                         val = nla_data(tb[i]);
 399                         len = nla_len(tb[i]);
 400
 401                         rc = load_metaops_and_vet(ife, i, val, len);
 402                         if (rc != 0)
 403                                 return rc;
 404
 405                         rc = add_metainfo(ife, i, val, len);
 406                         if (rc)
 407                                 return rc;
 408                 }
 409         }
 410
 411         return rc;
 412 }
 413
 414 static int tcf_ife_init(struct net *net, struct nlattr *nla,
 415                         struct nlattr *est, struct tc_action *a,
 416                         int ovr, int bind)
 417 {
 418         struct tc_action_net *tn = net_generic(net, ife_net_id);
 419         struct nlattr *tb[TCA_IFE_MAX + 1];
 420         struct nlattr *tb2[IFE_META_MAX + 1];
 421         struct tcf_ife_info *ife;
 422         struct tc_ife *parm;
 423         u16 ife_type = 0;
 424         u8 *daddr = NULL;
 425         u8 *saddr = NULL;
 426         int ret = 0;
 427         int err;
 428
 429         err = nla_parse_nested(tb, TCA_IFE_MAX, nla, ife_policy);
 430         if (err < 0)
 431                 return err;
 432
 433         if (!tb[TCA_IFE_PARMS])
 434                 return -EINVAL;
 435
 436         parm = nla_data(tb[TCA_IFE_PARMS]);
 437
 438         if (parm->flags & IFE_ENCODE) {
 439                 /* Until we get issued the ethertype, we cant have
 440                  * a default..
 441                 **/
 442                 if (!tb[TCA_IFE_TYPE]) {
 443                         pr_info("You MUST pass etherype for encoding\n");
 444                         return -EINVAL;
 445                 }
 446         }
 447
 448         if (!tcf_hash_check(tn, parm->index, a, bind)) {
 449                 ret = tcf_hash_create(tn, parm->index, est, a, sizeof(*ife),
 450                                       bind, false);
 451                 if (ret)
 452                         return ret;
 453                 ret = ACT_P_CREATED;
 454         } else {
 455                 if (bind)       /* dont override defaults */
 456                         return 0;
 457                 tcf_hash_release(a, bind);
 458                 if (!ovr)
 459                         return -EEXIST;
 460         }
 461
 462         ife = to_ife(a);
 463         ife->flags = parm->flags;
 464
 465         if (parm->flags & IFE_ENCODE) {
 466                 ife_type = nla_get_u16(tb[TCA_IFE_TYPE]);
 467                 if (tb[TCA_IFE_DMAC])
 468                         daddr = nla_data(tb[TCA_IFE_DMAC]);
 469                 if (tb[TCA_IFE_SMAC])
 470                         saddr = nla_data(tb[TCA_IFE_SMAC]);
 471         }
 472
 473         spin_lock_bh(&ife->tcf_lock);
 474         ife->tcf_action = parm->action;
 475
 476         if (parm->flags & IFE_ENCODE) {
 477                 if (daddr)
 478                         ether_addr_copy(ife->eth_dst, daddr);
 479                 else
 480                         eth_zero_addr(ife->eth_dst);
 481
 482                 if (saddr)
 483                         ether_addr_copy(ife->eth_src, saddr);
 484                 else
 485                         eth_zero_addr(ife->eth_src);
 486
 487                 ife->eth_type = ife_type;
 488         }
 489
 490         if (ret == ACT_P_CREATED)
 491                 INIT_LIST_HEAD(&ife->metalist);
 492
 493         if (tb[TCA_IFE_METALST]) {
 494                 err = nla_parse_nested(tb2, IFE_META_MAX, tb[TCA_IFE_METALST],
 495                                        NULL);
 496                 if (err) {
 497 metadata_parse_err:
 498                         if (ret == ACT_P_CREATED)
 499                                 _tcf_ife_cleanup(a, bind);
 500
 501                         spin_unlock_bh(&ife->tcf_lock);
 502                         return err;
 503                 }
 504
 505                 err = populate_metalist(ife, tb2);
 506                 if (err)
 507                         goto metadata_parse_err;
 508
 509         } else {
 510                 /* if no passed metadata allow list or passed allow-all
 511                  * then here we process by adding as many supported metadatum
 512                  * as we can. You better have at least one else we are
 513                  * going to bail out
 514                  */
 515                 err = use_all_metadata(ife);
 516                 if (err) {
 517                         if (ret == ACT_P_CREATED)
 518                                 _tcf_ife_cleanup(a, bind);
 519
 520                         spin_unlock_bh(&ife->tcf_lock);
 521                         return err;
 522                 }
 523         }
 524
 525         spin_unlock_bh(&ife->tcf_lock);
 526
 527         if (ret == ACT_P_CREATED)
 528                 tcf_hash_insert(tn, a);
 529
 530         return ret;
 531 }
 532
 533 static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 534                         int ref)
 535 {
 536         unsigned char *b = skb_tail_pointer(skb);
 537         struct tcf_ife_info *ife = a->priv;
 538         struct tc_ife opt = {
 539                 .index = ife->tcf_index,
 540                 .refcnt = ife->tcf_refcnt - ref,
 541                 .bindcnt = ife->tcf_bindcnt - bind,
 542                 .action = ife->tcf_action,
 543                 .flags = ife->flags,
 544         };
 545         struct tcf_t t;
 546
 547         if (nla_put(skb, TCA_IFE_PARMS, sizeof(opt), &opt))
 548                 goto nla_put_failure;
 549
 550         t.install = jiffies_to_clock_t(jiffies - ife->tcf_tm.install);
 551         t.lastuse = jiffies_to_clock_t(jiffies - ife->tcf_tm.lastuse);
 552         t.expires = jiffies_to_clock_t(ife->tcf_tm.expires);
 553         if (nla_put(skb, TCA_IFE_TM, sizeof(t), &t))
 554                 goto nla_put_failure;
 555
 556         if (!is_zero_ether_addr(ife->eth_dst)) {
 557                 if (nla_put(skb, TCA_IFE_DMAC, ETH_ALEN, ife->eth_dst))
 558                         goto nla_put_failure;
 559         }
 560
 561         if (!is_zero_ether_addr(ife->eth_src)) {
 562                 if (nla_put(skb, TCA_IFE_SMAC, ETH_ALEN, ife->eth_src))
 563                         goto nla_put_failure;
 564         }
 565
 566         if (nla_put(skb, TCA_IFE_TYPE, 2, &ife->eth_type))
 567                 goto nla_put_failure;
 568
 569         if (dump_metalist(skb, ife)) {
 570                 /*ignore failure to dump metalist */
 571                 pr_info("Failed to dump metalist\n");
 572         }
 573
 574         return skb->len;
 575
 576 nla_put_failure:
 577         nlmsg_trim(skb, b);
 578         return -1;
 579 }
 580
 581 int find_decode_metaid(struct sk_buff *skb, struct tcf_ife_info *ife,
 582                        u16 metaid, u16 mlen, void *mdata)
 583 {
 584         struct tcf_meta_info *e;
 585
 586         /* XXX: use hash to speed up */
 587         list_for_each_entry(e, &ife->metalist, metalist) {
 588                 if (metaid == e->metaid) {
 589                         if (e->ops) {
 590                                 /* We check for decode presence already */
 591                                 return e->ops->decode(skb, mdata, mlen);
 592                         }
 593                 }
 594         }
 595
 596         return 0;
 597 }
 598
 599 struct ifeheadr {
 600         __be16 metalen;
 601         u8 tlv_data[];
 602 };
 603
 604 struct meta_tlvhdr {
 605         __be16 type;
 606         __be16 len;
 607 };
 608
 609 static int tcf_ife_decode(struct sk_buff *skb, const struct tc_action *a,
 610                           struct tcf_result *res)
 611 {
 612         struct tcf_ife_info *ife = a->priv;
 613         int action = ife->tcf_action;
 614         struct ifeheadr *ifehdr = (struct ifeheadr *)skb->data;
 615         u16 ifehdrln = ifehdr->metalen;
 616         struct meta_tlvhdr *tlv = (struct meta_tlvhdr *)(ifehdr->tlv_data);
 617
 618         spin_lock(&ife->tcf_lock);
 619         bstats_update(&ife->tcf_bstats, skb);
 620         ife->tcf_tm.lastuse = jiffies;
 621         spin_unlock(&ife->tcf_lock);
 622
 623         ifehdrln = ntohs(ifehdrln);
 624         if (unlikely(!pskb_may_pull(skb, ifehdrln))) {
 625                 spin_lock(&ife->tcf_lock);
 626                 ife->tcf_qstats.drops++;
 627                 spin_unlock(&ife->tcf_lock);
 628                 return TC_ACT_SHOT;
 629         }
 630
 631         skb_set_mac_header(skb, ifehdrln);
 632         __skb_pull(skb, ifehdrln);
 633         skb->protocol = eth_type_trans(skb, skb->dev);
 634         ifehdrln -= IFE_METAHDRLEN;
 635
 636         while (ifehdrln > 0) {
 637                 u8 *tlvdata = (u8 *)tlv;
 638                 u16 mtype = tlv->type;
 639                 u16 mlen = tlv->len;
 640
 641                 mtype = ntohs(mtype);
 642                 mlen = ntohs(mlen);
 643
 644                 if (find_decode_metaid(skb, ife, mtype, (mlen - 4),
 645                                        (void *)(tlvdata + 4))) {
 646                         /* abuse overlimits to count when we receive metadata
 647                          * but dont have an ops for it
 648                          */
 649                         pr_info_ratelimited("Unknown metaid %d alnlen %d\n",
 650                                             mtype, mlen);
 651                         ife->tcf_qstats.overlimits++;
 652                 }
 653
 654                 tlvdata += mlen;
 655                 ifehdrln -= mlen;
 656                 tlv = (struct meta_tlvhdr *)tlvdata;
 657         }
 658
 659         skb_reset_network_header(skb);
 660         return action;
 661 }
 662
 663 /*XXX: check if we can do this at install time instead of current
 664  * send data path
 665 **/
 666 static int ife_get_sz(struct sk_buff *skb, struct tcf_ife_info *ife)
 667 {
 668         struct tcf_meta_info *e, *n;
 669         int tot_run_sz = 0, run_sz = 0;
 670
 671         list_for_each_entry_safe(e, n, &ife->metalist, metalist) {
 672                 if (e->ops->check_presence) {
 673                         run_sz = e->ops->check_presence(skb, e);
 674                         tot_run_sz += run_sz;
 675                 }
 676         }
 677
 678         return tot_run_sz;
 679 }
 680
 681 static int tcf_ife_encode(struct sk_buff *skb, const struct tc_action *a,
 682                           struct tcf_result *res)
 683 {
 684         struct tcf_ife_info *ife = a->priv;
 685         int action = ife->tcf_action;
 686         struct ethhdr *oethh;   /* outer ether header */
 687         struct ethhdr *iethh;   /* inner eth header */
 688         struct tcf_meta_info *e;
 689         /*
 690            OUTERHDR:TOTMETALEN:{TLVHDR:Metadatum:TLVHDR..}:ORIGDATA
 691            where ORIGDATA = original ethernet header ...
 692          */
 693         u16 metalen = ife_get_sz(skb, ife);
 694         int hdrm = metalen + skb->dev->hard_header_len + IFE_METAHDRLEN;
 695         unsigned int skboff = skb->dev->hard_header_len;
 696         u32 at = G_TC_AT(skb->tc_verd);
 697         int new_len = skb->len + hdrm;
 698         bool exceed_mtu = false;
 699         int err;
 700
 701         if (at & AT_EGRESS) {
 702                 if (new_len > skb->dev->mtu)
 703                         exceed_mtu = true;
 704         }
 705
 706         spin_lock(&ife->tcf_lock);
 707         bstats_update(&ife->tcf_bstats, skb);
 708         ife->tcf_tm.lastuse = jiffies;
 709
 710         if (!metalen) {         /* no metadata to send */
 711                 /* abuse overlimits to count when we allow packet
 712                  * with no metadata
 713                  */
 714                 ife->tcf_qstats.overlimits++;
 715                 spin_unlock(&ife->tcf_lock);
 716                 return action;
 717         }
 718         /* could be stupid policy setup or mtu config
 719          * so lets be conservative.. */
 720         if ((action == TC_ACT_SHOT) || exceed_mtu) {
 721                 ife->tcf_qstats.drops++;
 722                 spin_unlock(&ife->tcf_lock);
 723                 return TC_ACT_SHOT;
 724         }
 725
 726         iethh = eth_hdr(skb);
 727
 728         err = skb_cow_head(skb, hdrm);
 729         if (unlikely(err)) {
 730                 ife->tcf_qstats.drops++;
 731                 spin_unlock(&ife->tcf_lock);
 732                 return TC_ACT_SHOT;
 733         }
 734
 735         if (!(at & AT_EGRESS))
 736                 skb_push(skb, skb->dev->hard_header_len);
 737
 738         __skb_push(skb, hdrm);
 739         memcpy(skb->data, iethh, skb->mac_len);
 740         skb_reset_mac_header(skb);
 741         oethh = eth_hdr(skb);
 742
 743         /*total metadata length */
 744         metalen += IFE_METAHDRLEN;
 745         metalen = htons(metalen);
 746         memcpy((skb->data + skboff), &metalen, IFE_METAHDRLEN);
 747         skboff += IFE_METAHDRLEN;
 748
 749         /* XXX: we dont have a clever way of telling encode to
 750          * not repeat some of the computations that are done by
 751          * ops->presence_check...
 752          */
 753         list_for_each_entry(e, &ife->metalist, metalist) {
 754                 if (e->ops->encode) {
 755                         err = e->ops->encode(skb, (void *)(skb->data + skboff),
 756                                              e);
 757                 }
 758                 if (err < 0) {
 759                         /* too corrupt to keep around if overwritten */
 760                         ife->tcf_qstats.drops++;
 761                         spin_unlock(&ife->tcf_lock);
 762                         return TC_ACT_SHOT;
 763                 }
 764                 skboff += err;
 765         }
 766
 767         if (!is_zero_ether_addr(ife->eth_src))
 768                 ether_addr_copy(oethh->h_source, ife->eth_src);
 769         else
 770                 ether_addr_copy(oethh->h_source, iethh->h_source);
 771         if (!is_zero_ether_addr(ife->eth_dst))
 772                 ether_addr_copy(oethh->h_dest, ife->eth_dst);
 773         else
 774                 ether_addr_copy(oethh->h_dest, iethh->h_dest);
 775         oethh->h_proto = htons(ife->eth_type);
 776
 777         if (!(at & AT_EGRESS))
 778                 skb_pull(skb, skb->dev->hard_header_len);
 779
 780         spin_unlock(&ife->tcf_lock);
 781
 782         return action;
 783 }
 784
 785 static int tcf_ife_act(struct sk_buff *skb, const struct tc_action *a,
 786                        struct tcf_result *res)
 787 {
 788         struct tcf_ife_info *ife = a->priv;
 789
 790         if (ife->flags & IFE_ENCODE)
 791                 return tcf_ife_encode(skb, a, res);
 792
 793         if (!(ife->flags & IFE_ENCODE))
 794                 return tcf_ife_decode(skb, a, res);
 795
 796         pr_info_ratelimited("unknown failure(policy neither de/encode\n");
 797         spin_lock(&ife->tcf_lock);
 798         bstats_update(&ife->tcf_bstats, skb);
 799         ife->tcf_tm.lastuse = jiffies;
 800         ife->tcf_qstats.drops++;
 801         spin_unlock(&ife->tcf_lock);
 802
 803         return TC_ACT_SHOT;
 804 }
 805
 806 static int tcf_ife_walker(struct net *net, struct sk_buff *skb,
 807                           struct netlink_callback *cb, int type,
 808                           struct tc_action *a)
 809 {
 810         struct tc_action_net *tn = net_generic(net, ife_net_id);
 811
 812         return tcf_generic_walker(tn, skb, cb, type, a);
 813 }
 814
 815 static int tcf_ife_search(struct net *net, struct tc_action *a, u32 index)
 816 {
 817         struct tc_action_net *tn = net_generic(net, ife_net_id);
 818
 819         return tcf_hash_search(tn, a, index);
 820 }
 821
 822 static struct tc_action_ops act_ife_ops = {
 823         .kind = "ife",
 824         .type = TCA_ACT_IFE,
 825         .owner = THIS_MODULE,
 826         .act = tcf_ife_act,
 827         .dump = tcf_ife_dump,
 828         .cleanup = tcf_ife_cleanup,
 829         .init = tcf_ife_init,
 830         .walk = tcf_ife_walker,
 831         .lookup = tcf_ife_search,
 832 };
 833
 834 static __net_init int ife_init_net(struct net *net)
 835 {
 836         struct tc_action_net *tn = net_generic(net, ife_net_id);
 837
 838         return tc_action_net_init(tn, &act_ife_ops, IFE_TAB_MASK);
 839 }
 840
 841 static void __net_exit ife_exit_net(struct net *net)
 842 {
 843         struct tc_action_net *tn = net_generic(net, ife_net_id);
 844
 845         tc_action_net_exit(tn);
 846 }
 847
 848 static struct pernet_operations ife_net_ops = {
 849         .init = ife_init_net,
 850         .exit = ife_exit_net,
 851         .id   = &ife_net_id,
 852         .size = sizeof(struct tc_action_net),
 853 };
 854
 855 static int __init ife_init_module(void)
 856 {
 857         return tcf_register_action(&act_ife_ops, &ife_net_ops);
 858 }
 859
 860 static void __exit ife_cleanup_module(void)
 861 {
 862         tcf_unregister_action(&act_ife_ops, &ife_net_ops);
 863 }
 864
 865 module_init(ife_init_module);
 866 module_exit(ife_cleanup_module);
 867
 868 MODULE_AUTHOR("Jamal Hadi Salim(2015)");
 869 MODULE_DESCRIPTION("Inter-FE LFB action");
 870 MODULE_LICENSE("GPL");