// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * net/sched/ife.c      Inter-FE action based on ForCES WG InterFE LFB
 *
 *              Refer to:
 *              draft-ietf-forces-interfelfb-03
 *              and
 *              netdev01 paper:
 *              "Distributing Linux Traffic Control Classifier-Action
 *              Subsystem"
 *              Authors: Jamal Hadi Salim and Damascene M. Joachimpillai
 *
 * copyright Jamal Hadi Salim (2015)
*/

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/module.h>
#include <linux/init.h>
#include <net/net_namespace.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>
#include <uapi/linux/tc_act/tc_ife.h>
#include <net/tc_act/tc_ife.h>
#include <linux/etherdevice.h>
#include <net/ife.h>
#include <net/tc_wrapper.h>

static int max_metacnt = IFE_META_MAX + 1;
static struct tc_action_ops act_ife_ops;

static const struct nla_policy ife_policy[TCA_IFE_MAX + 1] = {
        [TCA_IFE_PARMS] = { .len = sizeof(struct tc_ife)},
        [TCA_IFE_DMAC] = { .len = ETH_ALEN},
        [TCA_IFE_SMAC] = { .len = ETH_ALEN},
        [TCA_IFE_TYPE] = { .type = NLA_U16},
};

int ife_encode_meta_u16(u16 metaval, void *skbdata, struct tcf_meta_info *mi)
{
        u16 edata = 0;

        if (mi->metaval)
                edata = *(u16 *)mi->metaval;
        else if (metaval)
                edata = metaval;

        if (!edata) /* will not encode */
                return 0;

        edata = htons(edata);
        return ife_tlv_meta_encode(skbdata, mi->metaid, 2, &edata);
}
EXPORT_SYMBOL_GPL(ife_encode_meta_u16);

int ife_get_meta_u32(struct sk_buff *skb, struct tcf_meta_info *mi)
{
        if (mi->metaval)
                return nla_put_u32(skb, mi->metaid, *(u32 *)mi->metaval);
        else
                return nla_put(skb, mi->metaid, 0, NULL);
}
EXPORT_SYMBOL_GPL(ife_get_meta_u32);

int ife_check_meta_u32(u32 metaval, struct tcf_meta_info *mi)
{
        if (metaval || mi->metaval)
                return 8; /* T+L+V == 2+2+4 */

        return 0;
}
EXPORT_SYMBOL_GPL(ife_check_meta_u32);

int ife_check_meta_u16(u16 metaval, struct tcf_meta_info *mi)
{
        if (metaval || mi->metaval)
                return 8; /* T+L+(V) == 2+2+(2+2bytepad) */

        return 0;
}
EXPORT_SYMBOL_GPL(ife_check_meta_u16);

int ife_encode_meta_u32(u32 metaval, void *skbdata, struct tcf_meta_info *mi)
{
        u32 edata = metaval;

        if (mi->metaval)
                edata = *(u32 *)mi->metaval;
        else if (metaval)
                edata = metaval;

        if (!edata) /* will not encode */
                return 0;

        edata = htonl(edata);
        return ife_tlv_meta_encode(skbdata, mi->metaid, 4, &edata);
}
EXPORT_SYMBOL_GPL(ife_encode_meta_u32);

int ife_get_meta_u16(struct sk_buff *skb, struct tcf_meta_info *mi)
{
        if (mi->metaval)
                return nla_put_u16(skb, mi->metaid, *(u16 *)mi->metaval);
        else
                return nla_put(skb, mi->metaid, 0, NULL);
}
EXPORT_SYMBOL_GPL(ife_get_meta_u16);

int ife_alloc_meta_u32(struct tcf_meta_info *mi, void *metaval, gfp_t gfp)
{
        mi->metaval = kmemdup(metaval, sizeof(u32), gfp);
        if (!mi->metaval)
                return -ENOMEM;

        return 0;
}
EXPORT_SYMBOL_GPL(ife_alloc_meta_u32);

int ife_alloc_meta_u16(struct tcf_meta_info *mi, void *metaval, gfp_t gfp)
{
        mi->metaval = kmemdup(metaval, sizeof(u16), gfp);
        if (!mi->metaval)
                return -ENOMEM;

        return 0;
}
EXPORT_SYMBOL_GPL(ife_alloc_meta_u16);

void ife_release_meta_gen(struct tcf_meta_info *mi)
{
        kfree(mi->metaval);
}
EXPORT_SYMBOL_GPL(ife_release_meta_gen);

int ife_validate_meta_u32(void *val, int len)
{
        if (len == sizeof(u32))
                return 0;

        return -EINVAL;
}
EXPORT_SYMBOL_GPL(ife_validate_meta_u32);

int ife_validate_meta_u16(void *val, int len)
{
        /* length will not include padding */
        if (len == sizeof(u16))
                return 0;

        return -EINVAL;
}
EXPORT_SYMBOL_GPL(ife_validate_meta_u16);

static LIST_HEAD(ifeoplist);
static DEFINE_RWLOCK(ife_mod_lock);

static struct tcf_meta_ops *find_ife_oplist(u16 metaid)
{
        struct tcf_meta_ops *o;

        read_lock(&ife_mod_lock);
        list_for_each_entry(o, &ifeoplist, list) {
                if (o->metaid == metaid) {
                        if (!try_module_get(o->owner))
                                o = NULL;
                        read_unlock(&ife_mod_lock);
                        return o;
                }
        }
        read_unlock(&ife_mod_lock);

        return NULL;
}

int register_ife_op(struct tcf_meta_ops *mops)
{
        struct tcf_meta_ops *m;

        if (!mops->metaid || !mops->metatype || !mops->name ||
            !mops->check_presence || !mops->encode || !mops->decode ||
            !mops->get || !mops->alloc)
                return -EINVAL;

        write_lock(&ife_mod_lock);

        list_for_each_entry(m, &ifeoplist, list) {
                if (m->metaid == mops->metaid ||
                    (strcmp(mops->name, m->name) == 0)) {
                        write_unlock(&ife_mod_lock);
                        return -EEXIST;
                }
        }

        if (!mops->release)
                mops->release = ife_release_meta_gen;

        list_add_tail(&mops->list, &ifeoplist);
        write_unlock(&ife_mod_lock);
        return 0;
}
EXPORT_SYMBOL_GPL(unregister_ife_op);

int unregister_ife_op(struct tcf_meta_ops *mops)
{
        struct tcf_meta_ops *m;
        int err = -ENOENT;

        write_lock(&ife_mod_lock);
        list_for_each_entry(m, &ifeoplist, list) {
                if (m->metaid == mops->metaid) {
                        list_del(&mops->list);
                        err = 0;
                        break;
                }
        }
        write_unlock(&ife_mod_lock);

        return err;
}
EXPORT_SYMBOL_GPL(register_ife_op);

static int ife_validate_metatype(struct tcf_meta_ops *ops, void *val, int len)
{
        int ret = 0;
        /* XXX: unfortunately cant use nla_policy at this point
        * because a length of 0 is valid in the case of
        * "allow". "use" semantics do enforce for proper
        * length and i couldve use nla_policy but it makes it hard
        * to use it just for that..
        */
        if (ops->validate)
                return ops->validate(val, len);

        if (ops->metatype == NLA_U32)
                ret = ife_validate_meta_u32(val, len);
        else if (ops->metatype == NLA_U16)
                ret = ife_validate_meta_u16(val, len);

        return ret;
}

#ifdef CONFIG_MODULES
static const char *ife_meta_id2name(u32 metaid)
{
        switch (metaid) {
        case IFE_META_SKBMARK:
                return "skbmark";
        case IFE_META_PRIO:
                return "skbprio";
        case IFE_META_TCINDEX:
                return "tcindex";
        default:
                return "unknown";
        }
}
#endif

/* called when adding new meta information
*/
static int load_metaops_and_vet(u32 metaid, void *val, int len, bool rtnl_held)
{
        struct tcf_meta_ops *ops = find_ife_oplist(metaid);
        int ret = 0;

        if (!ops) {
                ret = -ENOENT;
#ifdef CONFIG_MODULES
                if (rtnl_held)
                        rtnl_unlock();
                request_module("ife-meta-%s", ife_meta_id2name(metaid));
                if (rtnl_held)
                        rtnl_lock();
                ops = find_ife_oplist(metaid);
#endif
        }

        if (ops) {
                ret = 0;
                if (len)
                        ret = ife_validate_metatype(ops, val, len);

                module_put(ops->owner);
        }

        return ret;
}

/* called when adding new meta information
*/
static int __add_metainfo(const struct tcf_meta_ops *ops,
                          struct tcf_ife_params *p, u32 metaid, void *metaval,
                          int len, bool atomic)
{
        struct tcf_meta_info *mi = NULL;
        int ret = 0;

        mi = kzalloc_obj(*mi, atomic ? GFP_ATOMIC : GFP_KERNEL);
        if (!mi)
                return -ENOMEM;

        mi->metaid = metaid;
        mi->ops = ops;
        if (len > 0) {
                ret = ops->alloc(mi, metaval, atomic ? GFP_ATOMIC : GFP_KERNEL);
                if (ret != 0) {
                        kfree(mi);
                        return ret;
                }
        }

        list_add_tail(&mi->metalist, &p->metalist);

        return ret;
}

static int add_metainfo_and_get_ops(const struct tcf_meta_ops *ops,
                                    struct tcf_ife_params *p, u32 metaid)
{
        int ret;

        if (!try_module_get(ops->owner))
                return -ENOENT;
        ret = __add_metainfo(ops, p, metaid, NULL, 0, true);
        if (ret)
                module_put(ops->owner);
        return ret;
}

static int add_metainfo(struct tcf_ife_params *p, u32 metaid, void *metaval,
                        int len)
{
        const struct tcf_meta_ops *ops = find_ife_oplist(metaid);
        int ret;

        if (!ops)
                return -ENOENT;
        ret = __add_metainfo(ops, p, metaid, metaval, len, false);
        if (ret)
                /*put back what find_ife_oplist took */
                module_put(ops->owner);
        return ret;
}

static int use_all_metadata(struct tcf_ife_params *p)
{
        struct tcf_meta_ops *o;
        int rc = 0;
        int installed = 0;

        read_lock(&ife_mod_lock);
        list_for_each_entry(o, &ifeoplist, list) {
                rc = add_metainfo_and_get_ops(o, p, o->metaid);
                if (rc == 0)
                        installed += 1;
        }
        read_unlock(&ife_mod_lock);

        if (installed)
                return 0;
        else
                return -EINVAL;
}

static int dump_metalist(struct sk_buff *skb, struct tcf_ife_params *p)
{
        struct tcf_meta_info *e;
        struct nlattr *nest;
        unsigned char *b = skb_tail_pointer(skb);
        int total_encoded = 0;

        /*can only happen on decode */
        if (list_empty(&p->metalist))
                return 0;

        nest = nla_nest_start_noflag(skb, TCA_IFE_METALST);
        if (!nest)
                goto out_nlmsg_trim;

        list_for_each_entry(e, &p->metalist, metalist) {
                if (!e->ops->get(skb, e))
                        total_encoded += 1;
        }

        if (!total_encoded)
                goto out_nlmsg_trim;

        nla_nest_end(skb, nest);

        return 0;

out_nlmsg_trim:
        nlmsg_trim(skb, b);
        return -1;
}

static void __tcf_ife_cleanup(struct tcf_ife_params *p)
{
        struct tcf_meta_info *e, *n;

        list_for_each_entry_safe(e, n, &p->metalist, metalist) {
                list_del(&e->metalist);
                if (e->metaval) {
                        if (e->ops->release)
                                e->ops->release(e);
                        else
                                kfree(e->metaval);
                }
                module_put(e->ops->owner);
                kfree(e);
        }
}

static void tcf_ife_cleanup_params(struct rcu_head *head)
{
        struct tcf_ife_params *p = container_of(head, struct tcf_ife_params,
                                                rcu);

        __tcf_ife_cleanup(p);
        kfree(p);
}

static void tcf_ife_cleanup(struct tc_action *a)
{
        struct tcf_ife_info *ife = to_ife(a);
        struct tcf_ife_params *p;

        p = rcu_dereference_protected(ife->params, 1);
        if (p)
                call_rcu(&p->rcu, tcf_ife_cleanup_params);
}

static int load_metalist(struct nlattr **tb, bool rtnl_held)
{
        int i;

        for (i = 1; i < max_metacnt; i++) {
                if (tb[i]) {
                        void *val = nla_data(tb[i]);
                        int len = nla_len(tb[i]);
                        int rc;

                        rc = load_metaops_and_vet(i, val, len, rtnl_held);
                        if (rc != 0)
                                return rc;
                }
        }

        return 0;
}

static int populate_metalist(struct tcf_ife_params *p, struct nlattr **tb)
{
        int len = 0;
        int rc = 0;
        int i = 0;
        void *val;

        for (i = 1; i < max_metacnt; i++) {
                if (tb[i]) {
                        val = nla_data(tb[i]);
                        len = nla_len(tb[i]);

                        rc = add_metainfo(p, i, val, len);
                        if (rc)
                                return rc;
                }
        }

        return rc;
}

static int tcf_ife_init(struct net *net, struct nlattr *nla,
                        struct nlattr *est, struct tc_action **a,
                        struct tcf_proto *tp, u32 flags,
                        struct netlink_ext_ack *extack)
{
        struct tc_action_net *tn = net_generic(net, act_ife_ops.net_id);
        bool bind = flags & TCA_ACT_FLAGS_BIND;
        struct nlattr *tb[TCA_IFE_MAX + 1];
        struct nlattr *tb2[IFE_META_MAX + 1];
        struct tcf_chain *goto_ch = NULL;
        struct tcf_ife_params *p;
        struct tcf_ife_info *ife;
        u16 ife_type = ETH_P_IFE;
        struct tc_ife *parm;
        u8 *daddr = NULL;
        u8 *saddr = NULL;
        bool exists = false;
        int ret = 0;
        u32 index;
        int err;

        if (!nla) {
                NL_SET_ERR_MSG_MOD(extack, "IFE requires attributes to be passed");
                return -EINVAL;
        }

        err = nla_parse_nested_deprecated(tb, TCA_IFE_MAX, nla, ife_policy,
                                          NULL);
        if (err < 0)
                return err;

        if (!tb[TCA_IFE_PARMS])
                return -EINVAL;

        parm = nla_data(tb[TCA_IFE_PARMS]);

        /* IFE_DECODE is 0 and indicates the opposite of IFE_ENCODE because
         * they cannot run as the same time. Check on all other values which
         * are not supported right now.
         */
        if (parm->flags & ~IFE_ENCODE)
                return -EINVAL;

        p = kzalloc_obj(*p);
        if (!p)
                return -ENOMEM;
        INIT_LIST_HEAD(&p->metalist);

        if (tb[TCA_IFE_METALST]) {
                err = nla_parse_nested_deprecated(tb2, IFE_META_MAX,
                                                  tb[TCA_IFE_METALST], NULL,
                                                  NULL);
                if (err) {
                        kfree(p);
                        return err;
                }
                err = load_metalist(tb2, !(flags & TCA_ACT_FLAGS_NO_RTNL));
                if (err) {
                        kfree(p);
                        return err;
                }
        }

        index = parm->index;
        err = tcf_idr_check_alloc(tn, &index, a, bind);
        if (err < 0) {
                kfree(p);
                return err;
        }
        exists = err;
        if (exists && bind) {
                kfree(p);
                return ACT_P_BOUND;
        }

        if (!exists) {
                ret = tcf_idr_create(tn, index, est, a, &act_ife_ops,
                                     bind, true, flags);
                if (ret) {
                        tcf_idr_cleanup(tn, index);
                        kfree(p);
                        return ret;
                }
                ret = ACT_P_CREATED;
        } else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
                tcf_idr_release(*a, bind);
                kfree(p);
                return -EEXIST;
        }

        ife = to_ife(*a);

        err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
        if (err < 0)
                goto release_idr;

        p->flags = parm->flags;

        if (parm->flags & IFE_ENCODE) {
                if (tb[TCA_IFE_TYPE])
                        ife_type = nla_get_u16(tb[TCA_IFE_TYPE]);
                if (tb[TCA_IFE_DMAC])
                        daddr = nla_data(tb[TCA_IFE_DMAC]);
                if (tb[TCA_IFE_SMAC])
                        saddr = nla_data(tb[TCA_IFE_SMAC]);
        }

        if (parm->flags & IFE_ENCODE) {
                if (daddr)
                        ether_addr_copy(p->eth_dst, daddr);
                else
                        eth_zero_addr(p->eth_dst);

                if (saddr)
                        ether_addr_copy(p->eth_src, saddr);
                else
                        eth_zero_addr(p->eth_src);

                p->eth_type = ife_type;
        }

        if (tb[TCA_IFE_METALST]) {
                err = populate_metalist(p, tb2);
                if (err)
                        goto metadata_parse_err;
        } else {
                /* if no passed metadata allow list or passed allow-all
                 * then here we process by adding as many supported metadatum
                 * as we can. You better have at least one else we are
                 * going to bail out
                 */
                err = use_all_metadata(p);
                if (err)
                        goto metadata_parse_err;
        }

        if (exists)
                spin_lock_bh(&ife->tcf_lock);
        /* protected by tcf_lock when modifying existing action */
        goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
        p = rcu_replace_pointer(ife->params, p, 1);

        if (exists)
                spin_unlock_bh(&ife->tcf_lock);
        if (goto_ch)
                tcf_chain_put_by_act(goto_ch);
        if (p)
                call_rcu(&p->rcu, tcf_ife_cleanup_params);

        return ret;
metadata_parse_err:
        if (goto_ch)
                tcf_chain_put_by_act(goto_ch);
release_idr:
        __tcf_ife_cleanup(p);
        kfree(p);
        tcf_idr_release(*a, bind);
        return err;
}

static int tcf_ife_dump(struct sk_buff *skb, struct tc_action *a, int bind,
                        int ref)
{
        unsigned char *b = skb_tail_pointer(skb);
        struct tcf_ife_info *ife = to_ife(a);
        struct tcf_ife_params *p;
        struct tc_ife opt;
        struct tcf_t t;

        memset(&opt, 0, sizeof(opt));

        opt.index = ife->tcf_index;
        opt.refcnt = refcount_read(&ife->tcf_refcnt) - ref;
        opt.bindcnt = atomic_read(&ife->tcf_bindcnt) - bind;

        spin_lock_bh(&ife->tcf_lock);
        opt.action = ife->tcf_action;
        p = rcu_dereference_protected(ife->params,
                                      lockdep_is_held(&ife->tcf_lock));
        opt.flags = p->flags;

        if (nla_put(skb, TCA_IFE_PARMS, sizeof(opt), &opt))
                goto nla_put_failure;

        tcf_tm_dump(&t, &ife->tcf_tm);
        if (nla_put_64bit(skb, TCA_IFE_TM, sizeof(t), &t, TCA_IFE_PAD))
                goto nla_put_failure;

        if (!is_zero_ether_addr(p->eth_dst)) {
                if (nla_put(skb, TCA_IFE_DMAC, ETH_ALEN, p->eth_dst))
                        goto nla_put_failure;
        }

        if (!is_zero_ether_addr(p->eth_src)) {
                if (nla_put(skb, TCA_IFE_SMAC, ETH_ALEN, p->eth_src))
                        goto nla_put_failure;
        }

        if (nla_put(skb, TCA_IFE_TYPE, 2, &p->eth_type))
                goto nla_put_failure;

        if (dump_metalist(skb, p)) {
                /*ignore failure to dump metalist */
                pr_info("Failed to dump metalist\n");
        }

        spin_unlock_bh(&ife->tcf_lock);
        return skb->len;

nla_put_failure:
        spin_unlock_bh(&ife->tcf_lock);
        nlmsg_trim(skb, b);
        return -1;
}

static int find_decode_metaid(struct sk_buff *skb, struct tcf_ife_params *p,
                              u16 metaid, u16 mlen, void *mdata)
{
        struct tcf_meta_info *e;

        /* XXX: use hash to speed up */
        list_for_each_entry_rcu(e, &p->metalist, metalist) {
                if (metaid == e->metaid) {
                        if (e->ops) {
                                /* We check for decode presence already */
                                return e->ops->decode(skb, mdata, mlen);
                        }
                }
        }

        return -ENOENT;
}

static int tcf_ife_decode(struct sk_buff *skb, const struct tc_action *a,
                          struct tcf_result *res)
{
        struct tcf_ife_info *ife = to_ife(a);
        int action = ife->tcf_action;
        struct tcf_ife_params *p;
        u8 *ifehdr_end;
        u8 *tlv_data;
        u16 metalen;

        p = rcu_dereference_bh(ife->params);

        bstats_update(this_cpu_ptr(ife->common.cpu_bstats), skb);
        tcf_lastuse_update(&ife->tcf_tm);

        if (skb_at_tc_ingress(skb))
                skb_push(skb, skb->dev->hard_header_len);

        tlv_data = ife_decode(skb, &metalen);
        if (unlikely(!tlv_data)) {
                qstats_drop_inc(this_cpu_ptr(ife->common.cpu_qstats));
                return TC_ACT_SHOT;
        }

        ifehdr_end = tlv_data + metalen;
        for (; tlv_data < ifehdr_end; tlv_data = ife_tlv_meta_next(tlv_data)) {
                u8 *curr_data;
                u16 mtype;
                u16 dlen;

                curr_data = ife_tlv_meta_decode(tlv_data, ifehdr_end, &mtype,
                                                &dlen, NULL);
                if (!curr_data) {
                        qstats_drop_inc(this_cpu_ptr(ife->common.cpu_qstats));
                        return TC_ACT_SHOT;
                }

                if (find_decode_metaid(skb, p, mtype, dlen, curr_data)) {
                        /* abuse overlimits to count when we receive metadata
                         * but dont have an ops for it
                         */
                        pr_info_ratelimited("Unknown metaid %d dlen %d\n",
                                            mtype, dlen);
                        qstats_overlimit_inc(this_cpu_ptr(ife->common.cpu_qstats));
                }
        }

        if (WARN_ON(tlv_data != ifehdr_end)) {
                qstats_drop_inc(this_cpu_ptr(ife->common.cpu_qstats));
                return TC_ACT_SHOT;
        }

        skb->protocol = eth_type_trans(skb, skb->dev);
        skb_reset_network_header(skb);

        return action;
}

/*XXX: check if we can do this at install time instead of current
 * send data path
**/
static int ife_get_sz(struct sk_buff *skb, struct tcf_ife_params *p)
{
        struct tcf_meta_info *e;
        int tot_run_sz = 0, run_sz = 0;

        list_for_each_entry_rcu(e, &p->metalist, metalist) {
                if (e->ops->check_presence) {
                        run_sz = e->ops->check_presence(skb, e);
                        tot_run_sz += run_sz;
                }
        }

        return tot_run_sz;
}

static int tcf_ife_encode(struct sk_buff *skb, const struct tc_action *a,
                          struct tcf_result *res, struct tcf_ife_params *p)
{
        struct tcf_ife_info *ife = to_ife(a);
        int action = ife->tcf_action;
        struct ethhdr *oethh;   /* outer ether header */
        struct tcf_meta_info *e;
        /*
           OUTERHDR:TOTMETALEN:{TLVHDR:Metadatum:TLVHDR..}:ORIGDATA
           where ORIGDATA = original ethernet header ...
         */
        u16 metalen = ife_get_sz(skb, p);
        int hdrm = metalen + skb->dev->hard_header_len + IFE_METAHDRLEN;
        unsigned int skboff = 0;
        int new_len = skb->len + hdrm;
        bool exceed_mtu = false;
        void *ife_meta;
        int err = 0;

        if (!skb_at_tc_ingress(skb)) {
                if (new_len > skb->dev->mtu)
                        exceed_mtu = true;
        }

        bstats_update(this_cpu_ptr(ife->common.cpu_bstats), skb);
        tcf_lastuse_update(&ife->tcf_tm);

        if (!metalen) {         /* no metadata to send */
                /* abuse overlimits to count when we allow packet
                 * with no metadata
                 */
                qstats_overlimit_inc(this_cpu_ptr(ife->common.cpu_qstats));
                return action;
        }
        /* could be stupid policy setup or mtu config
         * so lets be conservative.. */
        if ((action == TC_ACT_SHOT) || exceed_mtu) {
drop:
                qstats_drop_inc(this_cpu_ptr(ife->common.cpu_qstats));
                return TC_ACT_SHOT;
        }

        if (skb_at_tc_ingress(skb))
                skb_push(skb, skb->dev->hard_header_len);

        ife_meta = ife_encode(skb, metalen);
        if (!ife_meta)
                goto drop;

        /* XXX: we dont have a clever way of telling encode to
         * not repeat some of the computations that are done by
         * ops->presence_check...
         */
        list_for_each_entry_rcu(e, &p->metalist, metalist) {
                if (e->ops->encode) {
                        err = e->ops->encode(skb, (void *)(ife_meta + skboff),
                                             e);
                }
                if (err < 0) {
                        /* too corrupt to keep around if overwritten */
                        goto drop;
                }
                skboff += err;
        }
        oethh = (struct ethhdr *)skb->data;

        if (!is_zero_ether_addr(p->eth_src))
                ether_addr_copy(oethh->h_source, p->eth_src);
        if (!is_zero_ether_addr(p->eth_dst))
                ether_addr_copy(oethh->h_dest, p->eth_dst);
        oethh->h_proto = htons(p->eth_type);

        if (skb_at_tc_ingress(skb))
                skb_pull(skb, skb->dev->hard_header_len);

        return action;
}

TC_INDIRECT_SCOPE int tcf_ife_act(struct sk_buff *skb,
                                  const struct tc_action *a,
                                  struct tcf_result *res)
{
        struct tcf_ife_info *ife = to_ife(a);
        struct tcf_ife_params *p;
        int ret;

        p = rcu_dereference_bh(ife->params);
        if (p->flags & IFE_ENCODE) {
                ret = tcf_ife_encode(skb, a, res, p);
                return ret;
        }

        return tcf_ife_decode(skb, a, res);
}

static struct tc_action_ops act_ife_ops = {
        .kind = "ife",
        .id = TCA_ID_IFE,
        .owner = THIS_MODULE,
        .act = tcf_ife_act,
        .dump = tcf_ife_dump,
        .cleanup = tcf_ife_cleanup,
        .init = tcf_ife_init,
        .size = sizeof(struct tcf_ife_info),
};
MODULE_ALIAS_NET_ACT("ife");

static __net_init int ife_init_net(struct net *net)
{
        struct tc_action_net *tn = net_generic(net, act_ife_ops.net_id);

        return tc_action_net_init(net, tn, &act_ife_ops);
}

static void __net_exit ife_exit_net(struct list_head *net_list)
{
        tc_action_net_exit(net_list, act_ife_ops.net_id);
}

static struct pernet_operations ife_net_ops = {
        .init = ife_init_net,
        .exit_batch = ife_exit_net,
        .id   = &act_ife_ops.net_id,
        .size = sizeof(struct tc_action_net),
};

static int __init ife_init_module(void)
{
        return tcf_register_action(&act_ife_ops, &ife_net_ops);
}

static void __exit ife_cleanup_module(void)
{
        tcf_unregister_action(&act_ife_ops, &ife_net_ops);
}

module_init(ife_init_module);
module_exit(ife_cleanup_module);

MODULE_AUTHOR("Jamal Hadi Salim(2015)");
MODULE_DESCRIPTION("Inter-FE LFB action");
MODULE_LICENSE("GPL");