linux/net/sched/act_ife.c
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   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
  38static unsigned int ife_net_id;
  39static int max_metacnt = IFE_META_MAX + 1;
  40static struct tc_action_ops act_ife_ops;
  41
  42static const struct nla_policy ife_policy[TCA_IFE_MAX + 1] = {
  43        [TCA_IFE_PARMS] = { .len = sizeof(struct tc_ife)},
  44        [TCA_IFE_DMAC] = { .len = ETH_ALEN},
  45        [TCA_IFE_SMAC] = { .len = ETH_ALEN},
  46        [TCA_IFE_TYPE] = { .type = NLA_U16},
  47};
  48
  49/* Caller takes care of presenting data in network order
  50*/
  51int ife_tlv_meta_encode(void *skbdata, u16 attrtype, u16 dlen, const void *dval)
  52{
  53        u32 *tlv = (u32 *)(skbdata);
  54        u16 totlen = nla_total_size(dlen);      /*alignment + hdr */
  55        char *dptr = (char *)tlv + NLA_HDRLEN;
  56        u32 htlv = attrtype << 16 | (dlen + NLA_HDRLEN);
  57
  58        *tlv = htonl(htlv);
  59        memset(dptr, 0, totlen - NLA_HDRLEN);
  60        memcpy(dptr, dval, dlen);
  61
  62        return totlen;
  63}
  64EXPORT_SYMBOL_GPL(ife_tlv_meta_encode);
  65
  66int ife_encode_meta_u16(u16 metaval, void *skbdata, struct tcf_meta_info *mi)
  67{
  68        u16 edata = 0;
  69
  70        if (mi->metaval)
  71                edata = *(u16 *)mi->metaval;
  72        else if (metaval)
  73                edata = metaval;
  74
  75        if (!edata) /* will not encode */
  76                return 0;
  77
  78        edata = htons(edata);
  79        return ife_tlv_meta_encode(skbdata, mi->metaid, 2, &edata);
  80}
  81EXPORT_SYMBOL_GPL(ife_encode_meta_u16);
  82
  83int ife_get_meta_u32(struct sk_buff *skb, struct tcf_meta_info *mi)
  84{
  85        if (mi->metaval)
  86                return nla_put_u32(skb, mi->metaid, *(u32 *)mi->metaval);
  87        else
  88                return nla_put(skb, mi->metaid, 0, NULL);
  89}
  90EXPORT_SYMBOL_GPL(ife_get_meta_u32);
  91
  92int ife_check_meta_u32(u32 metaval, struct tcf_meta_info *mi)
  93{
  94        if (metaval || mi->metaval)
  95                return 8; /* T+L+V == 2+2+4 */
  96
  97        return 0;
  98}
  99EXPORT_SYMBOL_GPL(ife_check_meta_u32);
 100
 101int ife_check_meta_u16(u16 metaval, struct tcf_meta_info *mi)
 102{
 103        if (metaval || mi->metaval)
 104                return 8; /* T+L+(V) == 2+2+(2+2bytepad) */
 105
 106        return 0;
 107}
 108EXPORT_SYMBOL_GPL(ife_check_meta_u16);
 109
 110int ife_encode_meta_u32(u32 metaval, void *skbdata, struct tcf_meta_info *mi)
 111{
 112        u32 edata = metaval;
 113
 114        if (mi->metaval)
 115                edata = *(u32 *)mi->metaval;
 116        else if (metaval)
 117                edata = metaval;
 118
 119        if (!edata) /* will not encode */
 120                return 0;
 121
 122        edata = htonl(edata);
 123        return ife_tlv_meta_encode(skbdata, mi->metaid, 4, &edata);
 124}
 125EXPORT_SYMBOL_GPL(ife_encode_meta_u32);
 126
 127int ife_get_meta_u16(struct sk_buff *skb, struct tcf_meta_info *mi)
 128{
 129        if (mi->metaval)
 130                return nla_put_u16(skb, mi->metaid, *(u16 *)mi->metaval);
 131        else
 132                return nla_put(skb, mi->metaid, 0, NULL);
 133}
 134EXPORT_SYMBOL_GPL(ife_get_meta_u16);
 135
 136int ife_alloc_meta_u32(struct tcf_meta_info *mi, void *metaval, gfp_t gfp)
 137{
 138        mi->metaval = kmemdup(metaval, sizeof(u32), gfp);
 139        if (!mi->metaval)
 140                return -ENOMEM;
 141
 142        return 0;
 143}
 144EXPORT_SYMBOL_GPL(ife_alloc_meta_u32);
 145
 146int ife_alloc_meta_u16(struct tcf_meta_info *mi, void *metaval, gfp_t gfp)
 147{
 148        mi->metaval = kmemdup(metaval, sizeof(u16), gfp);
 149        if (!mi->metaval)
 150                return -ENOMEM;
 151
 152        return 0;
 153}
 154EXPORT_SYMBOL_GPL(ife_alloc_meta_u16);
 155
 156void ife_release_meta_gen(struct tcf_meta_info *mi)
 157{
 158        kfree(mi->metaval);
 159}
 160EXPORT_SYMBOL_GPL(ife_release_meta_gen);
 161
 162int ife_validate_meta_u32(void *val, int len)
 163{
 164        if (len == sizeof(u32))
 165                return 0;
 166
 167        return -EINVAL;
 168}
 169EXPORT_SYMBOL_GPL(ife_validate_meta_u32);
 170
 171int ife_validate_meta_u16(void *val, int len)
 172{
 173        /* length will not include padding */
 174        if (len == sizeof(u16))
 175                return 0;
 176
 177        return -EINVAL;
 178}
 179EXPORT_SYMBOL_GPL(ife_validate_meta_u16);
 180
 181static LIST_HEAD(ifeoplist);
 182static DEFINE_RWLOCK(ife_mod_lock);
 183
 184static struct tcf_meta_ops *find_ife_oplist(u16 metaid)
 185{
 186        struct tcf_meta_ops *o;
 187
 188        read_lock(&ife_mod_lock);
 189        list_for_each_entry(o, &ifeoplist, list) {
 190                if (o->metaid == metaid) {
 191                        if (!try_module_get(o->owner))
 192                                o = NULL;
 193                        read_unlock(&ife_mod_lock);
 194                        return o;
 195                }
 196        }
 197        read_unlock(&ife_mod_lock);
 198
 199        return NULL;
 200}
 201
 202int register_ife_op(struct tcf_meta_ops *mops)
 203{
 204        struct tcf_meta_ops *m;
 205
 206        if (!mops->metaid || !mops->metatype || !mops->name ||
 207            !mops->check_presence || !mops->encode || !mops->decode ||
 208            !mops->get || !mops->alloc)
 209                return -EINVAL;
 210
 211        write_lock(&ife_mod_lock);
 212
 213        list_for_each_entry(m, &ifeoplist, list) {
 214                if (m->metaid == mops->metaid ||
 215                    (strcmp(mops->name, m->name) == 0)) {
 216                        write_unlock(&ife_mod_lock);
 217                        return -EEXIST;
 218                }
 219        }
 220
 221        if (!mops->release)
 222                mops->release = ife_release_meta_gen;
 223
 224        list_add_tail(&mops->list, &ifeoplist);
 225        write_unlock(&ife_mod_lock);
 226        return 0;
 227}
 228EXPORT_SYMBOL_GPL(unregister_ife_op);
 229
 230int unregister_ife_op(struct tcf_meta_ops *mops)
 231{
 232        struct tcf_meta_ops *m;
 233        int err = -ENOENT;
 234
 235        write_lock(&ife_mod_lock);
 236        list_for_each_entry(m, &ifeoplist, list) {
 237                if (m->metaid == mops->metaid) {
 238                        list_del(&mops->list);
 239                        err = 0;
 240                        break;
 241                }
 242        }
 243        write_unlock(&ife_mod_lock);
 244
 245        return err;
 246}
 247EXPORT_SYMBOL_GPL(register_ife_op);
 248
 249static int ife_validate_metatype(struct tcf_meta_ops *ops, void *val, int len)
 250{
 251        int ret = 0;
 252        /* XXX: unfortunately cant use nla_policy at this point
 253        * because a length of 0 is valid in the case of
 254        * "allow". "use" semantics do enforce for proper
 255        * length and i couldve use nla_policy but it makes it hard
 256        * to use it just for that..
 257        */
 258        if (ops->validate)
 259                return ops->validate(val, len);
 260
 261        if (ops->metatype == NLA_U32)
 262                ret = ife_validate_meta_u32(val, len);
 263        else if (ops->metatype == NLA_U16)
 264                ret = ife_validate_meta_u16(val, len);
 265
 266        return ret;
 267}
 268
 269/* called when adding new meta information
 270 * under ife->tcf_lock for existing action
 271*/
 272static int load_metaops_and_vet(struct tcf_ife_info *ife, u32 metaid,
 273                                void *val, int len, bool exists)
 274{
 275        struct tcf_meta_ops *ops = find_ife_oplist(metaid);
 276        int ret = 0;
 277
 278        if (!ops) {
 279                ret = -ENOENT;
 280#ifdef CONFIG_MODULES
 281                if (exists)
 282                        spin_unlock_bh(&ife->tcf_lock);
 283                rtnl_unlock();
 284                request_module("ifemeta%u", metaid);
 285                rtnl_lock();
 286                if (exists)
 287                        spin_lock_bh(&ife->tcf_lock);
 288                ops = find_ife_oplist(metaid);
 289#endif
 290        }
 291
 292        if (ops) {
 293                ret = 0;
 294                if (len)
 295                        ret = ife_validate_metatype(ops, val, len);
 296
 297                module_put(ops->owner);
 298        }
 299
 300        return ret;
 301}
 302
 303/* called when adding new meta information
 304 * under ife->tcf_lock for existing action
 305*/
 306static int add_metainfo(struct tcf_ife_info *ife, u32 metaid, void *metaval,
 307                        int len, bool atomic)
 308{
 309        struct tcf_meta_info *mi = NULL;
 310        struct tcf_meta_ops *ops = find_ife_oplist(metaid);
 311        int ret = 0;
 312
 313        if (!ops)
 314                return -ENOENT;
 315
 316        mi = kzalloc(sizeof(*mi), atomic ? GFP_ATOMIC : GFP_KERNEL);
 317        if (!mi) {
 318                /*put back what find_ife_oplist took */
 319                module_put(ops->owner);
 320                return -ENOMEM;
 321        }
 322
 323        mi->metaid = metaid;
 324        mi->ops = ops;
 325        if (len > 0) {
 326                ret = ops->alloc(mi, metaval, atomic ? GFP_ATOMIC : GFP_KERNEL);
 327                if (ret != 0) {
 328                        kfree(mi);
 329                        module_put(ops->owner);
 330                        return ret;
 331                }
 332        }
 333
 334        list_add_tail(&mi->metalist, &ife->metalist);
 335
 336        return ret;
 337}
 338
 339static int use_all_metadata(struct tcf_ife_info *ife)
 340{
 341        struct tcf_meta_ops *o;
 342        int rc = 0;
 343        int installed = 0;
 344
 345        read_lock(&ife_mod_lock);
 346        list_for_each_entry(o, &ifeoplist, list) {
 347                rc = add_metainfo(ife, o->metaid, NULL, 0, true);
 348                if (rc == 0)
 349                        installed += 1;
 350        }
 351        read_unlock(&ife_mod_lock);
 352
 353        if (installed)
 354                return 0;
 355        else
 356                return -EINVAL;
 357}
 358
 359static int dump_metalist(struct sk_buff *skb, struct tcf_ife_info *ife)
 360{
 361        struct tcf_meta_info *e;
 362        struct nlattr *nest;
 363        unsigned char *b = skb_tail_pointer(skb);
 364        int total_encoded = 0;
 365
 366        /*can only happen on decode */
 367        if (list_empty(&ife->metalist))
 368                return 0;
 369
 370        nest = nla_nest_start(skb, TCA_IFE_METALST);
 371        if (!nest)
 372                goto out_nlmsg_trim;
 373
 374        list_for_each_entry(e, &ife->metalist, metalist) {
 375                if (!e->ops->get(skb, e))
 376                        total_encoded += 1;
 377        }
 378
 379        if (!total_encoded)
 380                goto out_nlmsg_trim;
 381
 382        nla_nest_end(skb, nest);
 383
 384        return 0;
 385
 386out_nlmsg_trim:
 387        nlmsg_trim(skb, b);
 388        return -1;
 389}
 390
 391/* under ife->tcf_lock */
 392static void _tcf_ife_cleanup(struct tc_action *a, int bind)
 393{
 394        struct tcf_ife_info *ife = to_ife(a);
 395        struct tcf_meta_info *e, *n;
 396
 397        list_for_each_entry_safe(e, n, &ife->metalist, metalist) {
 398                module_put(e->ops->owner);
 399                list_del(&e->metalist);
 400                if (e->metaval) {
 401                        if (e->ops->release)
 402                                e->ops->release(e);
 403                        else
 404                                kfree(e->metaval);
 405                }
 406                kfree(e);
 407        }
 408}
 409
 410static void tcf_ife_cleanup(struct tc_action *a, int bind)
 411{
 412        struct tcf_ife_info *ife = to_ife(a);
 413
 414        spin_lock_bh(&ife->tcf_lock);
 415        _tcf_ife_cleanup(a, bind);
 416        spin_unlock_bh(&ife->tcf_lock);
 417}
 418
 419/* under ife->tcf_lock for existing action */
 420static int populate_metalist(struct tcf_ife_info *ife, struct nlattr **tb,
 421                             bool exists)
 422{
 423        int len = 0;
 424        int rc = 0;
 425        int i = 0;
 426        void *val;
 427
 428        for (i = 1; i < max_metacnt; i++) {
 429                if (tb[i]) {
 430                        val = nla_data(tb[i]);
 431                        len = nla_len(tb[i]);
 432
 433                        rc = load_metaops_and_vet(ife, i, val, len, exists);
 434                        if (rc != 0)
 435                                return rc;
 436
 437                        rc = add_metainfo(ife, i, val, len, exists);
 438                        if (rc)
 439                                return rc;
 440                }
 441        }
 442
 443        return rc;
 444}
 445
 446static int tcf_ife_init(struct net *net, struct nlattr *nla,
 447                        struct nlattr *est, struct tc_action **a,
 448                        int ovr, int bind)
 449{
 450        struct tc_action_net *tn = net_generic(net, ife_net_id);
 451        struct nlattr *tb[TCA_IFE_MAX + 1];
 452        struct nlattr *tb2[IFE_META_MAX + 1];
 453        struct tcf_ife_info *ife;
 454        struct tc_ife *parm;
 455        u16 ife_type = 0;
 456        u8 *daddr = NULL;
 457        u8 *saddr = NULL;
 458        bool exists = false;
 459        int ret = 0;
 460        int err;
 461
 462        err = nla_parse_nested(tb, TCA_IFE_MAX, nla, ife_policy);
 463        if (err < 0)
 464                return err;
 465
 466        if (!tb[TCA_IFE_PARMS])
 467                return -EINVAL;
 468
 469        parm = nla_data(tb[TCA_IFE_PARMS]);
 470
 471        exists = tcf_hash_check(tn, parm->index, a, bind);
 472        if (exists && bind)
 473                return 0;
 474
 475        if (parm->flags & IFE_ENCODE) {
 476                /* Until we get issued the ethertype, we cant have
 477                 * a default..
 478                **/
 479                if (!tb[TCA_IFE_TYPE]) {
 480                        if (exists)
 481                                tcf_hash_release(*a, bind);
 482                        pr_info("You MUST pass etherype for encoding\n");
 483                        return -EINVAL;
 484                }
 485        }
 486
 487        if (!exists) {
 488                ret = tcf_hash_create(tn, parm->index, est, a, &act_ife_ops,
 489                                      bind, false);
 490                if (ret)
 491                        return ret;
 492                ret = ACT_P_CREATED;
 493        } else {
 494                tcf_hash_release(*a, bind);
 495                if (!ovr)
 496                        return -EEXIST;
 497        }
 498
 499        ife = to_ife(*a);
 500        ife->flags = parm->flags;
 501
 502        if (parm->flags & IFE_ENCODE) {
 503                ife_type = nla_get_u16(tb[TCA_IFE_TYPE]);
 504                if (tb[TCA_IFE_DMAC])
 505                        daddr = nla_data(tb[TCA_IFE_DMAC]);
 506                if (tb[TCA_IFE_SMAC])
 507                        saddr = nla_data(tb[TCA_IFE_SMAC]);
 508        }
 509
 510        if (exists)
 511                spin_lock_bh(&ife->tcf_lock);
 512        ife->tcf_action = parm->action;
 513
 514        if (parm->flags & IFE_ENCODE) {
 515                if (daddr)
 516                        ether_addr_copy(ife->eth_dst, daddr);
 517                else
 518                        eth_zero_addr(ife->eth_dst);
 519
 520                if (saddr)
 521                        ether_addr_copy(ife->eth_src, saddr);
 522                else
 523                        eth_zero_addr(ife->eth_src);
 524
 525                ife->eth_type = ife_type;
 526        }
 527
 528        if (ret == ACT_P_CREATED)
 529                INIT_LIST_HEAD(&ife->metalist);
 530
 531        if (tb[TCA_IFE_METALST]) {
 532                err = nla_parse_nested(tb2, IFE_META_MAX, tb[TCA_IFE_METALST],
 533                                       NULL);
 534                if (err) {
 535metadata_parse_err:
 536                        if (exists)
 537                                tcf_hash_release(*a, bind);
 538                        if (ret == ACT_P_CREATED)
 539                                _tcf_ife_cleanup(*a, bind);
 540
 541                        if (exists)
 542                                spin_unlock_bh(&ife->tcf_lock);
 543                        return err;
 544                }
 545
 546                err = populate_metalist(ife, tb2, exists);
 547                if (err)
 548                        goto metadata_parse_err;
 549
 550        } else {
 551                /* if no passed metadata allow list or passed allow-all
 552                 * then here we process by adding as many supported metadatum
 553                 * as we can. You better have at least one else we are
 554                 * going to bail out
 555                 */
 556                err = use_all_metadata(ife);
 557                if (err) {
 558                        if (ret == ACT_P_CREATED)
 559                                _tcf_ife_cleanup(*a, bind);
 560
 561                        if (exists)
 562                                spin_unlock_bh(&ife->tcf_lock);
 563                        return err;
 564                }
 565        }
 566
 567        if (exists)
 568                spin_unlock_bh(&ife->tcf_lock);
 569
 570        if (ret == ACT_P_CREATED)
 571                tcf_hash_insert(tn, *a);
 572
 573        return ret;
 574}
 575
 576static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind,
 577                        int ref)
 578{
 579        unsigned char *b = skb_tail_pointer(skb);
 580        struct tcf_ife_info *ife = to_ife(a);
 581        struct tc_ife opt = {
 582                .index = ife->tcf_index,
 583                .refcnt = ife->tcf_refcnt - ref,
 584                .bindcnt = ife->tcf_bindcnt - bind,
 585                .action = ife->tcf_action,
 586                .flags = ife->flags,
 587        };
 588        struct tcf_t t;
 589
 590        if (nla_put(skb, TCA_IFE_PARMS, sizeof(opt), &opt))
 591                goto nla_put_failure;
 592
 593        tcf_tm_dump(&t, &ife->tcf_tm);
 594        if (nla_put_64bit(skb, TCA_IFE_TM, sizeof(t), &t, TCA_IFE_PAD))
 595                goto nla_put_failure;
 596
 597        if (!is_zero_ether_addr(ife->eth_dst)) {
 598                if (nla_put(skb, TCA_IFE_DMAC, ETH_ALEN, ife->eth_dst))
 599                        goto nla_put_failure;
 600        }
 601
 602        if (!is_zero_ether_addr(ife->eth_src)) {
 603                if (nla_put(skb, TCA_IFE_SMAC, ETH_ALEN, ife->eth_src))
 604                        goto nla_put_failure;
 605        }
 606
 607        if (nla_put(skb, TCA_IFE_TYPE, 2, &ife->eth_type))
 608                goto nla_put_failure;
 609
 610        if (dump_metalist(skb, ife)) {
 611                /*ignore failure to dump metalist */
 612                pr_info("Failed to dump metalist\n");
 613        }
 614
 615        return skb->len;
 616
 617nla_put_failure:
 618        nlmsg_trim(skb, b);
 619        return -1;
 620}
 621
 622int find_decode_metaid(struct sk_buff *skb, struct tcf_ife_info *ife,
 623                       u16 metaid, u16 mlen, void *mdata)
 624{
 625        struct tcf_meta_info *e;
 626
 627        /* XXX: use hash to speed up */
 628        list_for_each_entry(e, &ife->metalist, metalist) {
 629                if (metaid == e->metaid) {
 630                        if (e->ops) {
 631                                /* We check for decode presence already */
 632                                return e->ops->decode(skb, mdata, mlen);
 633                        }
 634                }
 635        }
 636
 637        return 0;
 638}
 639
 640struct ifeheadr {
 641        __be16 metalen;
 642        u8 tlv_data[];
 643};
 644
 645struct meta_tlvhdr {
 646        __be16 type;
 647        __be16 len;
 648};
 649
 650static int tcf_ife_decode(struct sk_buff *skb, const struct tc_action *a,
 651                          struct tcf_result *res)
 652{
 653        struct tcf_ife_info *ife = to_ife(a);
 654        int action = ife->tcf_action;
 655        struct ifeheadr *ifehdr = (struct ifeheadr *)skb->data;
 656        int ifehdrln = (int)ifehdr->metalen;
 657        struct meta_tlvhdr *tlv = (struct meta_tlvhdr *)(ifehdr->tlv_data);
 658
 659        spin_lock(&ife->tcf_lock);
 660        bstats_update(&ife->tcf_bstats, skb);
 661        tcf_lastuse_update(&ife->tcf_tm);
 662        spin_unlock(&ife->tcf_lock);
 663
 664        ifehdrln = ntohs(ifehdrln);
 665        if (unlikely(!pskb_may_pull(skb, ifehdrln))) {
 666                spin_lock(&ife->tcf_lock);
 667                ife->tcf_qstats.drops++;
 668                spin_unlock(&ife->tcf_lock);
 669                return TC_ACT_SHOT;
 670        }
 671
 672        skb_set_mac_header(skb, ifehdrln);
 673        __skb_pull(skb, ifehdrln);
 674        skb->protocol = eth_type_trans(skb, skb->dev);
 675        ifehdrln -= IFE_METAHDRLEN;
 676
 677        while (ifehdrln > 0) {
 678                u8 *tlvdata = (u8 *)tlv;
 679                u16 mtype = tlv->type;
 680                u16 mlen = tlv->len;
 681                u16 alen;
 682
 683                mtype = ntohs(mtype);
 684                mlen = ntohs(mlen);
 685                alen = NLA_ALIGN(mlen);
 686
 687                if (find_decode_metaid(skb, ife, mtype, (mlen - NLA_HDRLEN),
 688                                       (void *)(tlvdata + NLA_HDRLEN))) {
 689                        /* abuse overlimits to count when we receive metadata
 690                         * but dont have an ops for it
 691                         */
 692                        pr_info_ratelimited("Unknown metaid %d alnlen %d\n",
 693                                            mtype, mlen);
 694                        ife->tcf_qstats.overlimits++;
 695                }
 696
 697                tlvdata += alen;
 698                ifehdrln -= alen;
 699                tlv = (struct meta_tlvhdr *)tlvdata;
 700        }
 701
 702        skb_reset_network_header(skb);
 703        return action;
 704}
 705
 706/*XXX: check if we can do this at install time instead of current
 707 * send data path
 708**/
 709static int ife_get_sz(struct sk_buff *skb, struct tcf_ife_info *ife)
 710{
 711        struct tcf_meta_info *e, *n;
 712        int tot_run_sz = 0, run_sz = 0;
 713
 714        list_for_each_entry_safe(e, n, &ife->metalist, metalist) {
 715                if (e->ops->check_presence) {
 716                        run_sz = e->ops->check_presence(skb, e);
 717                        tot_run_sz += run_sz;
 718                }
 719        }
 720
 721        return tot_run_sz;
 722}
 723
 724static int tcf_ife_encode(struct sk_buff *skb, const struct tc_action *a,
 725                          struct tcf_result *res)
 726{
 727        struct tcf_ife_info *ife = to_ife(a);
 728        int action = ife->tcf_action;
 729        struct ethhdr *oethh;   /* outer ether header */
 730        struct ethhdr *iethh;   /* inner eth header */
 731        struct tcf_meta_info *e;
 732        /*
 733           OUTERHDR:TOTMETALEN:{TLVHDR:Metadatum:TLVHDR..}:ORIGDATA
 734           where ORIGDATA = original ethernet header ...
 735         */
 736        u16 metalen = ife_get_sz(skb, ife);
 737        int hdrm = metalen + skb->dev->hard_header_len + IFE_METAHDRLEN;
 738        unsigned int skboff = skb->dev->hard_header_len;
 739        u32 at = G_TC_AT(skb->tc_verd);
 740        int new_len = skb->len + hdrm;
 741        bool exceed_mtu = false;
 742        int err;
 743
 744        if (at & AT_EGRESS) {
 745                if (new_len > skb->dev->mtu)
 746                        exceed_mtu = true;
 747        }
 748
 749        spin_lock(&ife->tcf_lock);
 750        bstats_update(&ife->tcf_bstats, skb);
 751        tcf_lastuse_update(&ife->tcf_tm);
 752
 753        if (!metalen) {         /* no metadata to send */
 754                /* abuse overlimits to count when we allow packet
 755                 * with no metadata
 756                 */
 757                ife->tcf_qstats.overlimits++;
 758                spin_unlock(&ife->tcf_lock);
 759                return action;
 760        }
 761        /* could be stupid policy setup or mtu config
 762         * so lets be conservative.. */
 763        if ((action == TC_ACT_SHOT) || exceed_mtu) {
 764                ife->tcf_qstats.drops++;
 765                spin_unlock(&ife->tcf_lock);
 766                return TC_ACT_SHOT;
 767        }
 768
 769        err = skb_cow_head(skb, hdrm);
 770        if (unlikely(err)) {
 771                ife->tcf_qstats.drops++;
 772                spin_unlock(&ife->tcf_lock);
 773                return TC_ACT_SHOT;
 774        }
 775
 776        if (!(at & AT_EGRESS))
 777                skb_push(skb, skb->dev->hard_header_len);
 778
 779        iethh = (struct ethhdr *)skb->data;
 780        __skb_push(skb, hdrm);
 781        memcpy(skb->data, iethh, skb->mac_len);
 782        skb_reset_mac_header(skb);
 783        oethh = eth_hdr(skb);
 784
 785        /*total metadata length */
 786        metalen += IFE_METAHDRLEN;
 787        metalen = htons(metalen);
 788        memcpy((skb->data + skboff), &metalen, IFE_METAHDRLEN);
 789        skboff += IFE_METAHDRLEN;
 790
 791        /* XXX: we dont have a clever way of telling encode to
 792         * not repeat some of the computations that are done by
 793         * ops->presence_check...
 794         */
 795        list_for_each_entry(e, &ife->metalist, metalist) {
 796                if (e->ops->encode) {
 797                        err = e->ops->encode(skb, (void *)(skb->data + skboff),
 798                                             e);
 799                }
 800                if (err < 0) {
 801                        /* too corrupt to keep around if overwritten */
 802                        ife->tcf_qstats.drops++;
 803                        spin_unlock(&ife->tcf_lock);
 804                        return TC_ACT_SHOT;
 805                }
 806                skboff += err;
 807        }
 808
 809        if (!is_zero_ether_addr(ife->eth_src))
 810                ether_addr_copy(oethh->h_source, ife->eth_src);
 811        else
 812                ether_addr_copy(oethh->h_source, iethh->h_source);
 813        if (!is_zero_ether_addr(ife->eth_dst))
 814                ether_addr_copy(oethh->h_dest, ife->eth_dst);
 815        else
 816                ether_addr_copy(oethh->h_dest, iethh->h_dest);
 817        oethh->h_proto = htons(ife->eth_type);
 818
 819        if (!(at & AT_EGRESS))
 820                skb_pull(skb, skb->dev->hard_header_len);
 821
 822        spin_unlock(&ife->tcf_lock);
 823
 824        return action;
 825}
 826
 827static int tcf_ife_act(struct sk_buff *skb, const struct tc_action *a,
 828                       struct tcf_result *res)
 829{
 830        struct tcf_ife_info *ife = to_ife(a);
 831
 832        if (ife->flags & IFE_ENCODE)
 833                return tcf_ife_encode(skb, a, res);
 834
 835        if (!(ife->flags & IFE_ENCODE))
 836                return tcf_ife_decode(skb, a, res);
 837
 838        pr_info_ratelimited("unknown failure(policy neither de/encode\n");
 839        spin_lock(&ife->tcf_lock);
 840        bstats_update(&ife->tcf_bstats, skb);
 841        tcf_lastuse_update(&ife->tcf_tm);
 842        ife->tcf_qstats.drops++;
 843        spin_unlock(&ife->tcf_lock);
 844
 845        return TC_ACT_SHOT;
 846}
 847
 848static int tcf_ife_walker(struct net *net, struct sk_buff *skb,
 849                          struct netlink_callback *cb, int type,
 850                          const struct tc_action_ops *ops)
 851{
 852        struct tc_action_net *tn = net_generic(net, ife_net_id);
 853
 854        return tcf_generic_walker(tn, skb, cb, type, ops);
 855}
 856
 857static int tcf_ife_search(struct net *net, struct tc_action **a, u32 index)
 858{
 859        struct tc_action_net *tn = net_generic(net, ife_net_id);
 860
 861        return tcf_hash_search(tn, a, index);
 862}
 863
 864static struct tc_action_ops act_ife_ops = {
 865        .kind = "ife",
 866        .type = TCA_ACT_IFE,
 867        .owner = THIS_MODULE,
 868        .act = tcf_ife_act,
 869        .dump = tcf_ife_dump,
 870        .cleanup = tcf_ife_cleanup,
 871        .init = tcf_ife_init,
 872        .walk = tcf_ife_walker,
 873        .lookup = tcf_ife_search,
 874        .size = sizeof(struct tcf_ife_info),
 875};
 876
 877static __net_init int ife_init_net(struct net *net)
 878{
 879        struct tc_action_net *tn = net_generic(net, ife_net_id);
 880
 881        return tc_action_net_init(tn, &act_ife_ops, IFE_TAB_MASK);
 882}
 883
 884static void __net_exit ife_exit_net(struct net *net)
 885{
 886        struct tc_action_net *tn = net_generic(net, ife_net_id);
 887
 888        tc_action_net_exit(tn);
 889}
 890
 891static struct pernet_operations ife_net_ops = {
 892        .init = ife_init_net,
 893        .exit = ife_exit_net,
 894        .id   = &ife_net_id,
 895        .size = sizeof(struct tc_action_net),
 896};
 897
 898static int __init ife_init_module(void)
 899{
 900        return tcf_register_action(&act_ife_ops, &ife_net_ops);
 901}
 902
 903static void __exit ife_cleanup_module(void)
 904{
 905        tcf_unregister_action(&act_ife_ops, &ife_net_ops);
 906}
 907
 908module_init(ife_init_module);
 909module_exit(ife_cleanup_module);
 910
 911MODULE_AUTHOR("Jamal Hadi Salim(2015)");
 912MODULE_DESCRIPTION("Inter-FE LFB action");
 913MODULE_LICENSE("GPL");
 914