sch_ingress.c

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/* net/sched/sch_ingress.c - Ingress qdisc
 *              This program is free software; you can redistribute it and/or
 *              modify it under the terms of the GNU General Public License
 *              as published by the Free Software Foundation; either version
 *              2 of the License, or (at your option) any later version.
 *
 * Authors:     Jamal Hadi Salim 1999
 */

#include <linux/module.h>
#include <linux/types.h>
#include <linux/list.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>


struct ingress_qdisc_data {
    struct tcf_proto    *filter_list;
};

/* ------------------------- Class/flow operations ------------------------- */

static struct Qdisc *ingress_leaf(struct Qdisc *sch, unsigned long arg)
{
    return NULL;
}

static unsigned long ingress_get(struct Qdisc *sch, u32 classid)
{
    return TC_H_MIN(classid) + 1;
}

static unsigned long ingress_bind_filter(struct Qdisc *sch,
                     unsigned long parent, u32 classid)
{
    return ingress_get(sch, classid);
}

static void ingress_put(struct Qdisc *sch, unsigned long cl)
{
}

static void ingress_walk(struct Qdisc *sch, struct qdisc_walker *walker)
{
}

static struct tcf_proto **ingress_find_tcf(struct Qdisc *sch, unsigned long cl)
{
    struct ingress_qdisc_data *p = qdisc_priv(sch);

    return &p->filter_list;
}

/* --------------------------- Qdisc operations ---------------------------- */

static int ingress_enqueue(struct sk_buff *skb, struct Qdisc *sch)
{
    struct ingress_qdisc_data *p = qdisc_priv(sch);
    struct tcf_result res;
    int result;

    result = tc_classify(skb, p->filter_list, &res);

    qdisc_bstats_update(sch, skb);
    switch (result) {
    case TC_ACT_SHOT:
        result = TC_ACT_SHOT;
        sch->qstats.drops++;
        break;
    case TC_ACT_STOLEN:
    case TC_ACT_QUEUED:
        result = TC_ACT_STOLEN;
        break;
    case TC_ACT_RECLASSIFY:
    case TC_ACT_OK:
        skb->tc_index = TC_H_MIN(res.classid);
    default:
        result = TC_ACT_OK;
        break;
    }

    return result;
}

/* ------------------------------------------------------------- */

static void ingress_destroy(struct Qdisc *sch)
{
    struct ingress_qdisc_data *p = qdisc_priv(sch);

    tcf_destroy_chain(&p->filter_list);
}

static int ingress_dump(struct Qdisc *sch, struct sk_buff *skb)
{
    struct nlattr *nest;

    nest = nla_nest_start(skb, TCA_OPTIONS);
    if (nest == NULL)
        goto nla_put_failure;
    nla_nest_end(skb, nest);
    return skb->len;

nla_put_failure:
    nla_nest_cancel(skb, nest);
    return -1;
}

static const struct Qdisc_class_ops ingress_class_ops = {
    .leaf       =   ingress_leaf,
    .get        =   ingress_get,
    .put        =   ingress_put,
    .walk       =   ingress_walk,
    .tcf_chain  =   ingress_find_tcf,
    .bind_tcf   =   ingress_bind_filter,
    .unbind_tcf =   ingress_put,
};

static struct Qdisc_ops ingress_qdisc_ops __read_mostly = {
    .cl_ops     =   &ingress_class_ops,
    .id     =   "ingress",
    .priv_size  =   sizeof(struct ingress_qdisc_data),
    .enqueue    =   ingress_enqueue,
    .destroy    =   ingress_destroy,
    .dump       =   ingress_dump,
    .owner      =   THIS_MODULE,
};

static int __init ingress_module_init(void)
{
    return register_qdisc(&ingress_qdisc_ops);
}

static void __exit ingress_module_exit(void)
{
    unregister_qdisc(&ingress_qdisc_ops);
}

module_init(ingress_module_init)
module_exit(ingress_module_exit)
MODULE_LICENSE("GPL");