root/net/sched/cls_matchall.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * net/sched/cls_matchll.c              Match-all classifier
 *
 * Copyright (c) 2016 Jiri Pirko <jiri@mellanox.com>
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/percpu.h>

#include <net/sch_generic.h>
#include <net/pkt_cls.h>
#include <net/tc_wrapper.h>

struct cls_mall_head {
        struct tcf_exts exts;
        struct tcf_result res;
        u32 handle;
        u32 flags;
        unsigned int in_hw_count;
        struct tc_matchall_pcnt __percpu *pf;
        struct rcu_work rwork;
        bool deleting;
};

TC_INDIRECT_SCOPE int mall_classify(struct sk_buff *skb,
                                    const struct tcf_proto *tp,
                                    struct tcf_result *res)
{
        struct cls_mall_head *head = rcu_dereference_bh(tp->root);

        if (unlikely(!head))
                return -1;

        if (tc_skip_sw(head->flags))
                return -1;

        *res = head->res;
        __this_cpu_inc(head->pf->rhit);
        return tcf_exts_exec(skb, &head->exts, res);
}

static int mall_init(struct tcf_proto *tp)
{
        return 0;
}

static void __mall_destroy(struct cls_mall_head *head)
{
        tcf_exts_destroy(&head->exts);
        tcf_exts_put_net(&head->exts);
        free_percpu(head->pf);
        kfree(head);
}

static void mall_destroy_work(struct work_struct *work)
{
        struct cls_mall_head *head = container_of(to_rcu_work(work),
                                                  struct cls_mall_head,
                                                  rwork);
        rtnl_lock();
        __mall_destroy(head);
        rtnl_unlock();
}

static void mall_destroy_hw_filter(struct tcf_proto *tp,
                                   struct cls_mall_head *head,
                                   unsigned long cookie,
                                   struct netlink_ext_ack *extack)
{
        struct tc_cls_matchall_offload cls_mall = {};
        struct tcf_block *block = tp->chain->block;

        tc_cls_common_offload_init(&cls_mall.common, tp, head->flags, extack);
        cls_mall.command = TC_CLSMATCHALL_DESTROY;
        cls_mall.cookie = cookie;

        tc_setup_cb_destroy(block, tp, TC_SETUP_CLSMATCHALL, &cls_mall, false,
                            &head->flags, &head->in_hw_count, true);
}

static int mall_replace_hw_filter(struct tcf_proto *tp,
                                  struct cls_mall_head *head,
                                  unsigned long cookie,
                                  struct netlink_ext_ack *extack)
{
        struct tc_cls_matchall_offload cls_mall = {};
        struct tcf_block *block = tp->chain->block;
        bool skip_sw = tc_skip_sw(head->flags);
        int err;

        cls_mall.rule = flow_rule_alloc(tcf_exts_num_actions(&head->exts));
        if (!cls_mall.rule)
                return -ENOMEM;

        tc_cls_common_offload_init(&cls_mall.common, tp, head->flags, extack);
        cls_mall.command = TC_CLSMATCHALL_REPLACE;
        cls_mall.cookie = cookie;

        err = tc_setup_offload_action(&cls_mall.rule->action, &head->exts,
                                      cls_mall.common.extack);
        if (err) {
                kfree(cls_mall.rule);
                mall_destroy_hw_filter(tp, head, cookie, NULL);

                return skip_sw ? err : 0;
        }

        err = tc_setup_cb_add(block, tp, TC_SETUP_CLSMATCHALL, &cls_mall,
                              skip_sw, &head->flags, &head->in_hw_count, true);
        tc_cleanup_offload_action(&cls_mall.rule->action);
        kfree(cls_mall.rule);

        if (err) {
                mall_destroy_hw_filter(tp, head, cookie, NULL);
                return err;
        }

        if (skip_sw && !(head->flags & TCA_CLS_FLAGS_IN_HW))
                return -EINVAL;

        return 0;
}

static void mall_destroy(struct tcf_proto *tp, bool rtnl_held,
                         struct netlink_ext_ack *extack)
{
        struct cls_mall_head *head = rtnl_dereference(tp->root);

        if (!head)
                return;

        tcf_unbind_filter(tp, &head->res);

        if (!tc_skip_hw(head->flags))
                mall_destroy_hw_filter(tp, head, (unsigned long) head, extack);

        if (tcf_exts_get_net(&head->exts))
                tcf_queue_work(&head->rwork, mall_destroy_work);
        else
                __mall_destroy(head);
}

static void *mall_get(struct tcf_proto *tp, u32 handle)
{
        struct cls_mall_head *head = rtnl_dereference(tp->root);

        if (head && head->handle == handle)
                return head;

        return NULL;
}

static const struct nla_policy mall_policy[TCA_MATCHALL_MAX + 1] = {
        [TCA_MATCHALL_UNSPEC]           = { .type = NLA_UNSPEC },
        [TCA_MATCHALL_CLASSID]          = { .type = NLA_U32 },
        [TCA_MATCHALL_FLAGS]            = { .type = NLA_U32 },
};

static int mall_change(struct net *net, struct sk_buff *in_skb,
                       struct tcf_proto *tp, unsigned long base,
                       u32 handle, struct nlattr **tca,
                       void **arg, u32 flags,
                       struct netlink_ext_ack *extack)
{
        struct cls_mall_head *head = rtnl_dereference(tp->root);
        struct nlattr *tb[TCA_MATCHALL_MAX + 1];
        bool bound_to_filter = false;
        struct cls_mall_head *new;
        u32 userflags = 0;
        int err;

        if (!tca[TCA_OPTIONS])
                return -EINVAL;

        if (head)
                return -EEXIST;

        err = nla_parse_nested_deprecated(tb, TCA_MATCHALL_MAX,
                                          tca[TCA_OPTIONS], mall_policy, NULL);
        if (err < 0)
                return err;

        if (tb[TCA_MATCHALL_FLAGS]) {
                userflags = nla_get_u32(tb[TCA_MATCHALL_FLAGS]);
                if (!tc_flags_valid(userflags))
                        return -EINVAL;
        }

        new = kzalloc_obj(*new);
        if (!new)
                return -ENOBUFS;

        err = tcf_exts_init(&new->exts, net, TCA_MATCHALL_ACT, 0);
        if (err)
                goto err_exts_init;

        if (!handle)
                handle = 1;
        new->handle = handle;
        new->flags = userflags;
        new->pf = alloc_percpu(struct tc_matchall_pcnt);
        if (!new->pf) {
                err = -ENOMEM;
                goto err_alloc_percpu;
        }

        err = tcf_exts_validate_ex(net, tp, tb, tca[TCA_RATE],
                                   &new->exts, flags, new->flags, extack);
        if (err < 0)
                goto err_set_parms;

        if (tb[TCA_MATCHALL_CLASSID]) {
                new->res.classid = nla_get_u32(tb[TCA_MATCHALL_CLASSID]);
                tcf_bind_filter(tp, &new->res, base);
                bound_to_filter = true;
        }

        if (!tc_skip_hw(new->flags)) {
                err = mall_replace_hw_filter(tp, new, (unsigned long)new,
                                             extack);
                if (err)
                        goto err_replace_hw_filter;
        }

        if (!tc_in_hw(new->flags))
                new->flags |= TCA_CLS_FLAGS_NOT_IN_HW;

        tcf_proto_update_usesw(tp, new->flags);

        *arg = head;
        rcu_assign_pointer(tp->root, new);
        return 0;

err_replace_hw_filter:
        if (bound_to_filter)
                tcf_unbind_filter(tp, &new->res);
err_set_parms:
        free_percpu(new->pf);
err_alloc_percpu:
        tcf_exts_destroy(&new->exts);
err_exts_init:
        kfree(new);
        return err;
}

static int mall_delete(struct tcf_proto *tp, void *arg, bool *last,
                       bool rtnl_held, struct netlink_ext_ack *extack)
{
        struct cls_mall_head *head = rtnl_dereference(tp->root);

        head->deleting = true;
        *last = true;
        return 0;
}

static void mall_walk(struct tcf_proto *tp, struct tcf_walker *arg,
                      bool rtnl_held)
{
        struct cls_mall_head *head = rtnl_dereference(tp->root);

        if (arg->count < arg->skip)
                goto skip;

        if (!head || head->deleting)
                return;
        if (arg->fn(tp, head, arg) < 0)
                arg->stop = 1;
skip:
        arg->count++;
}

static int mall_reoffload(struct tcf_proto *tp, bool add, flow_setup_cb_t *cb,
                          void *cb_priv, struct netlink_ext_ack *extack)
{
        struct cls_mall_head *head = rtnl_dereference(tp->root);
        struct tc_cls_matchall_offload cls_mall = {};
        struct tcf_block *block = tp->chain->block;
        int err;

        if (tc_skip_hw(head->flags))
                return 0;

        cls_mall.rule = flow_rule_alloc(tcf_exts_num_actions(&head->exts));
        if (!cls_mall.rule)
                return -ENOMEM;

        tc_cls_common_offload_init(&cls_mall.common, tp, head->flags, extack);
        cls_mall.command = add ?
                TC_CLSMATCHALL_REPLACE : TC_CLSMATCHALL_DESTROY;
        cls_mall.cookie = (unsigned long)head;

        err = tc_setup_offload_action(&cls_mall.rule->action, &head->exts,
                                      cls_mall.common.extack);
        if (err) {
                kfree(cls_mall.rule);

                return add && tc_skip_sw(head->flags) ? err : 0;
        }

        err = tc_setup_cb_reoffload(block, tp, add, cb, TC_SETUP_CLSMATCHALL,
                                    &cls_mall, cb_priv, &head->flags,
                                    &head->in_hw_count);
        tc_cleanup_offload_action(&cls_mall.rule->action);
        kfree(cls_mall.rule);

        return err;
}

static void mall_stats_hw_filter(struct tcf_proto *tp,
                                 struct cls_mall_head *head,
                                 unsigned long cookie)
{
        struct tc_cls_matchall_offload cls_mall = {};
        struct tcf_block *block = tp->chain->block;

        tc_cls_common_offload_init(&cls_mall.common, tp, head->flags, NULL);
        cls_mall.command = TC_CLSMATCHALL_STATS;
        cls_mall.cookie = cookie;

        tc_setup_cb_call(block, TC_SETUP_CLSMATCHALL, &cls_mall, false, true);

        tcf_exts_hw_stats_update(&head->exts, &cls_mall.stats, cls_mall.use_act_stats);
}

static int mall_dump(struct net *net, struct tcf_proto *tp, void *fh,
                     struct sk_buff *skb, struct tcmsg *t, bool rtnl_held)
{
        struct tc_matchall_pcnt gpf = {};
        struct cls_mall_head *head = fh;
        struct nlattr *nest;
        int cpu;

        if (!head)
                return skb->len;

        if (!tc_skip_hw(head->flags))
                mall_stats_hw_filter(tp, head, (unsigned long)head);

        t->tcm_handle = head->handle;

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

        if (head->res.classid &&
            nla_put_u32(skb, TCA_MATCHALL_CLASSID, head->res.classid))
                goto nla_put_failure;

        if (head->flags && nla_put_u32(skb, TCA_MATCHALL_FLAGS, head->flags))
                goto nla_put_failure;

        for_each_possible_cpu(cpu) {
                struct tc_matchall_pcnt *pf = per_cpu_ptr(head->pf, cpu);

                gpf.rhit += pf->rhit;
        }

        if (nla_put_64bit(skb, TCA_MATCHALL_PCNT,
                          sizeof(struct tc_matchall_pcnt),
                          &gpf, TCA_MATCHALL_PAD))
                goto nla_put_failure;

        if (tcf_exts_dump(skb, &head->exts))
                goto nla_put_failure;

        nla_nest_end(skb, nest);

        if (tcf_exts_dump_stats(skb, &head->exts) < 0)
                goto nla_put_failure;

        return skb->len;

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

static void mall_bind_class(void *fh, u32 classid, unsigned long cl, void *q,
                            unsigned long base)
{
        struct cls_mall_head *head = fh;

        tc_cls_bind_class(classid, cl, q, &head->res, base);
}

static struct tcf_proto_ops cls_mall_ops __read_mostly = {
        .kind           = "matchall",
        .classify       = mall_classify,
        .init           = mall_init,
        .destroy        = mall_destroy,
        .get            = mall_get,
        .change         = mall_change,
        .delete         = mall_delete,
        .walk           = mall_walk,
        .reoffload      = mall_reoffload,
        .dump           = mall_dump,
        .bind_class     = mall_bind_class,
        .owner          = THIS_MODULE,
};
MODULE_ALIAS_NET_CLS("matchall");

static int __init cls_mall_init(void)
{
        return register_tcf_proto_ops(&cls_mall_ops);
}

static void __exit cls_mall_exit(void)
{
        unregister_tcf_proto_ops(&cls_mall_ops);
}

module_init(cls_mall_init);
module_exit(cls_mall_exit);

MODULE_AUTHOR("Jiri Pirko <jiri@mellanox.com>");
MODULE_DESCRIPTION("Match-all classifier");
MODULE_LICENSE("GPL v2");