root/net/sched/sch_ingress.c
// SPDX-License-Identifier: GPL-2.0-or-later
/* net/sched/sch_ingress.c - Ingress and clsact qdisc
 *
 * 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>
#include <net/pkt_cls.h>
#include <net/tcx.h>

struct ingress_sched_data {
        struct tcf_block *block;
        struct tcf_block_ext_info block_info;
        struct mini_Qdisc_pair miniqp;
};

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

static unsigned long ingress_find(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_find(sch, classid);
}

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

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

static struct tcf_block *ingress_tcf_block(struct Qdisc *sch, unsigned long cl,
                                           struct netlink_ext_ack *extack)
{
        struct ingress_sched_data *q = qdisc_priv(sch);

        return q->block;
}

static void clsact_chain_head_change(struct tcf_proto *tp_head, void *priv)
{
        struct mini_Qdisc_pair *miniqp = priv;

        mini_qdisc_pair_swap(miniqp, tp_head);
};

static void ingress_ingress_block_set(struct Qdisc *sch, u32 block_index)
{
        struct ingress_sched_data *q = qdisc_priv(sch);

        q->block_info.block_index = block_index;
}

static u32 ingress_ingress_block_get(struct Qdisc *sch)
{
        struct ingress_sched_data *q = qdisc_priv(sch);

        return q->block_info.block_index;
}

static int ingress_init(struct Qdisc *sch, struct nlattr *opt,
                        struct netlink_ext_ack *extack)
{
        struct ingress_sched_data *q = qdisc_priv(sch);
        struct net_device *dev = qdisc_dev(sch);
        struct bpf_mprog_entry *entry;
        bool created;
        int err;

        if (sch->parent != TC_H_INGRESS)
                return -EOPNOTSUPP;

        net_inc_ingress_queue();

        entry = tcx_entry_fetch_or_create(dev, true, &created);
        if (!entry)
                return -ENOMEM;
        tcx_miniq_inc(entry);
        mini_qdisc_pair_init(&q->miniqp, sch, &tcx_entry(entry)->miniq);
        if (created)
                tcx_entry_update(dev, entry, true);

        q->block_info.binder_type = FLOW_BLOCK_BINDER_TYPE_CLSACT_INGRESS;
        q->block_info.chain_head_change = clsact_chain_head_change;
        q->block_info.chain_head_change_priv = &q->miniqp;

        err = tcf_block_get_ext(&q->block, sch, &q->block_info, extack);
        if (err)
                return err;

        mini_qdisc_pair_block_init(&q->miniqp, q->block);

        return 0;
}

static void ingress_destroy(struct Qdisc *sch)
{
        struct ingress_sched_data *q = qdisc_priv(sch);
        struct net_device *dev = qdisc_dev(sch);
        struct bpf_mprog_entry *entry;

        if (sch->parent != TC_H_INGRESS)
                return;

        tcf_block_put_ext(q->block, sch, &q->block_info);

        if (mini_qdisc_pair_inited(&q->miniqp)) {
                entry = rtnl_dereference(dev->tcx_ingress);
                tcx_miniq_dec(entry);
                if (!tcx_entry_is_active(entry)) {
                        tcx_entry_update(dev, NULL, true);
                        tcx_entry_free(entry);
                }
        }

        net_dec_ingress_queue();
}

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

        nest = nla_nest_start_noflag(skb, TCA_OPTIONS);
        if (nest == NULL)
                goto nla_put_failure;

        return nla_nest_end(skb, nest);

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

static const struct Qdisc_class_ops ingress_class_ops = {
        .flags          =       QDISC_CLASS_OPS_DOIT_UNLOCKED,
        .leaf           =       ingress_leaf,
        .find           =       ingress_find,
        .walk           =       ingress_walk,
        .tcf_block      =       ingress_tcf_block,
        .bind_tcf       =       ingress_bind_filter,
        .unbind_tcf     =       ingress_unbind_filter,
};

static struct Qdisc_ops ingress_qdisc_ops __read_mostly = {
        .cl_ops                 =       &ingress_class_ops,
        .id                     =       "ingress",
        .priv_size              =       sizeof(struct ingress_sched_data),
        .static_flags           =       TCQ_F_INGRESS | TCQ_F_CPUSTATS,
        .init                   =       ingress_init,
        .destroy                =       ingress_destroy,
        .dump                   =       ingress_dump,
        .ingress_block_set      =       ingress_ingress_block_set,
        .ingress_block_get      =       ingress_ingress_block_get,
        .owner                  =       THIS_MODULE,
};
MODULE_ALIAS_NET_SCH("ingress");

struct clsact_sched_data {
        struct tcf_block *ingress_block;
        struct tcf_block *egress_block;
        struct tcf_block_ext_info ingress_block_info;
        struct tcf_block_ext_info egress_block_info;
        struct mini_Qdisc_pair miniqp_ingress;
        struct mini_Qdisc_pair miniqp_egress;
};

static unsigned long clsact_find(struct Qdisc *sch, u32 classid)
{
        switch (TC_H_MIN(classid)) {
        case TC_H_MIN(TC_H_MIN_INGRESS):
        case TC_H_MIN(TC_H_MIN_EGRESS):
                return TC_H_MIN(classid);
        default:
                return 0;
        }
}

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

static struct tcf_block *clsact_tcf_block(struct Qdisc *sch, unsigned long cl,
                                          struct netlink_ext_ack *extack)
{
        struct clsact_sched_data *q = qdisc_priv(sch);

        switch (cl) {
        case TC_H_MIN(TC_H_MIN_INGRESS):
                return q->ingress_block;
        case TC_H_MIN(TC_H_MIN_EGRESS):
                return q->egress_block;
        default:
                return NULL;
        }
}

static void clsact_ingress_block_set(struct Qdisc *sch, u32 block_index)
{
        struct clsact_sched_data *q = qdisc_priv(sch);

        q->ingress_block_info.block_index = block_index;
}

static void clsact_egress_block_set(struct Qdisc *sch, u32 block_index)
{
        struct clsact_sched_data *q = qdisc_priv(sch);

        q->egress_block_info.block_index = block_index;
}

static u32 clsact_ingress_block_get(struct Qdisc *sch)
{
        struct clsact_sched_data *q = qdisc_priv(sch);

        return q->ingress_block_info.block_index;
}

static u32 clsact_egress_block_get(struct Qdisc *sch)
{
        struct clsact_sched_data *q = qdisc_priv(sch);

        return q->egress_block_info.block_index;
}

static int clsact_init(struct Qdisc *sch, struct nlattr *opt,
                       struct netlink_ext_ack *extack)
{
        struct clsact_sched_data *q = qdisc_priv(sch);
        struct net_device *dev = qdisc_dev(sch);
        struct bpf_mprog_entry *entry;
        bool created;
        int err;

        if (sch->parent != TC_H_CLSACT)
                return -EOPNOTSUPP;

        net_inc_ingress_queue();
        net_inc_egress_queue();

        entry = tcx_entry_fetch_or_create(dev, true, &created);
        if (!entry)
                return -ENOMEM;
        tcx_miniq_inc(entry);
        mini_qdisc_pair_init(&q->miniqp_ingress, sch, &tcx_entry(entry)->miniq);
        if (created)
                tcx_entry_update(dev, entry, true);

        q->ingress_block_info.binder_type = FLOW_BLOCK_BINDER_TYPE_CLSACT_INGRESS;
        q->ingress_block_info.chain_head_change = clsact_chain_head_change;
        q->ingress_block_info.chain_head_change_priv = &q->miniqp_ingress;

        err = tcf_block_get_ext(&q->ingress_block, sch, &q->ingress_block_info,
                                extack);
        if (err)
                return err;

        mini_qdisc_pair_block_init(&q->miniqp_ingress, q->ingress_block);

        entry = tcx_entry_fetch_or_create(dev, false, &created);
        if (!entry)
                return -ENOMEM;
        tcx_miniq_inc(entry);
        mini_qdisc_pair_init(&q->miniqp_egress, sch, &tcx_entry(entry)->miniq);
        if (created)
                tcx_entry_update(dev, entry, false);

        q->egress_block_info.binder_type = FLOW_BLOCK_BINDER_TYPE_CLSACT_EGRESS;
        q->egress_block_info.chain_head_change = clsact_chain_head_change;
        q->egress_block_info.chain_head_change_priv = &q->miniqp_egress;

        return tcf_block_get_ext(&q->egress_block, sch, &q->egress_block_info, extack);
}

static void clsact_destroy(struct Qdisc *sch)
{
        struct bpf_mprog_entry *ingress_entry, *egress_entry;
        struct clsact_sched_data *q = qdisc_priv(sch);
        struct net_device *dev = qdisc_dev(sch);

        if (sch->parent != TC_H_CLSACT)
                return;

        tcf_block_put_ext(q->ingress_block, sch, &q->ingress_block_info);
        tcf_block_put_ext(q->egress_block, sch, &q->egress_block_info);

        if (mini_qdisc_pair_inited(&q->miniqp_ingress)) {
                ingress_entry = rtnl_dereference(dev->tcx_ingress);
                tcx_miniq_dec(ingress_entry);
                if (!tcx_entry_is_active(ingress_entry)) {
                        tcx_entry_update(dev, NULL, true);
                        tcx_entry_free(ingress_entry);
                }
        }

        if (mini_qdisc_pair_inited(&q->miniqp_egress)) {
                egress_entry = rtnl_dereference(dev->tcx_egress);
                tcx_miniq_dec(egress_entry);
                if (!tcx_entry_is_active(egress_entry)) {
                        tcx_entry_update(dev, NULL, false);
                        tcx_entry_free(egress_entry);
                }
        }

        net_dec_ingress_queue();
        net_dec_egress_queue();
}

static const struct Qdisc_class_ops clsact_class_ops = {
        .flags          =       QDISC_CLASS_OPS_DOIT_UNLOCKED,
        .leaf           =       ingress_leaf,
        .find           =       clsact_find,
        .walk           =       ingress_walk,
        .tcf_block      =       clsact_tcf_block,
        .bind_tcf       =       clsact_bind_filter,
        .unbind_tcf     =       ingress_unbind_filter,
};

static struct Qdisc_ops clsact_qdisc_ops __read_mostly = {
        .cl_ops                 =       &clsact_class_ops,
        .id                     =       "clsact",
        .priv_size              =       sizeof(struct clsact_sched_data),
        .static_flags           =       TCQ_F_INGRESS | TCQ_F_CPUSTATS,
        .init                   =       clsact_init,
        .destroy                =       clsact_destroy,
        .dump                   =       ingress_dump,
        .ingress_block_set      =       clsact_ingress_block_set,
        .egress_block_set       =       clsact_egress_block_set,
        .ingress_block_get      =       clsact_ingress_block_get,
        .egress_block_get       =       clsact_egress_block_get,
        .owner                  =       THIS_MODULE,
};
MODULE_ALIAS_NET_SCH("clsact");

static int __init ingress_module_init(void)
{
        int ret;

        ret = register_qdisc(&ingress_qdisc_ops);
        if (!ret) {
                ret = register_qdisc(&clsact_qdisc_ops);
                if (ret)
                        unregister_qdisc(&ingress_qdisc_ops);
        }

        return ret;
}

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

module_init(ingress_module_init);
module_exit(ingress_module_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Ingress and clsact based ingress and egress qdiscs");