root/net/sched/act_police.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * net/sched/act_police.c       Input police filter
 *
 * Authors:     Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
 *              J Hadi Salim (action changes)
 */

#include <linux/module.h>
#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/init.h>
#include <linux/slab.h>
#include <net/act_api.h>
#include <net/gso.h>
#include <net/netlink.h>
#include <net/pkt_cls.h>
#include <net/tc_act/tc_police.h>
#include <net/tc_wrapper.h>

/* Each policer is serialized by its individual spinlock */

static struct tc_action_ops act_police_ops;

static const struct nla_policy police_policy[TCA_POLICE_MAX + 1] = {
        [TCA_POLICE_RATE]       = { .len = TC_RTAB_SIZE },
        [TCA_POLICE_PEAKRATE]   = { .len = TC_RTAB_SIZE },
        [TCA_POLICE_AVRATE]     = { .type = NLA_U32 },
        [TCA_POLICE_RESULT]     = { .type = NLA_U32 },
        [TCA_POLICE_RATE64]     = { .type = NLA_U64 },
        [TCA_POLICE_PEAKRATE64] = { .type = NLA_U64 },
        [TCA_POLICE_PKTRATE64]  = { .type = NLA_U64, .min = 1 },
        [TCA_POLICE_PKTBURST64] = { .type = NLA_U64, .min = 1 },
};

static int tcf_police_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)
{
        int ret = 0, tcfp_result = TC_ACT_OK, err, size;
        bool bind = flags & TCA_ACT_FLAGS_BIND;
        struct nlattr *tb[TCA_POLICE_MAX + 1];
        struct tcf_chain *goto_ch = NULL;
        struct tc_police *parm;
        struct tcf_police *police;
        struct qdisc_rate_table *R_tab = NULL, *P_tab = NULL;
        struct tc_action_net *tn = net_generic(net, act_police_ops.net_id);
        struct tcf_police_params *new;
        bool exists = false;
        u32 index;
        u64 rate64, prate64;
        u64 pps, ppsburst;

        if (nla == NULL)
                return -EINVAL;

        err = nla_parse_nested_deprecated(tb, TCA_POLICE_MAX, nla,
                                          police_policy, NULL);
        if (err < 0)
                return err;

        if (tb[TCA_POLICE_TBF] == NULL)
                return -EINVAL;
        size = nla_len(tb[TCA_POLICE_TBF]);
        if (size != sizeof(*parm) && size != sizeof(struct tc_police_compat))
                return -EINVAL;

        parm = nla_data(tb[TCA_POLICE_TBF]);
        index = parm->index;
        err = tcf_idr_check_alloc(tn, &index, a, bind);
        if (err < 0)
                return err;
        exists = err;
        if (exists && bind)
                return ACT_P_BOUND;

        if (!exists) {
                ret = tcf_idr_create(tn, index, NULL, a,
                                     &act_police_ops, bind, true, flags);
                if (ret) {
                        tcf_idr_cleanup(tn, index);
                        return ret;
                }
                ret = ACT_P_CREATED;
                spin_lock_init(&(to_police(*a)->tcfp_lock));
        } else if (!(flags & TCA_ACT_FLAGS_REPLACE)) {
                tcf_idr_release(*a, bind);
                return -EEXIST;
        }
        err = tcf_action_check_ctrlact(parm->action, tp, &goto_ch, extack);
        if (err < 0)
                goto release_idr;

        police = to_police(*a);
        if (parm->rate.rate) {
                err = -ENOMEM;
                R_tab = qdisc_get_rtab(&parm->rate, tb[TCA_POLICE_RATE], NULL);
                if (R_tab == NULL)
                        goto failure;

                if (parm->peakrate.rate) {
                        P_tab = qdisc_get_rtab(&parm->peakrate,
                                               tb[TCA_POLICE_PEAKRATE], NULL);
                        if (P_tab == NULL)
                                goto failure;
                }
        }

        if (est) {
                err = gen_replace_estimator(&police->tcf_bstats,
                                            police->common.cpu_bstats,
                                            &police->tcf_rate_est,
                                            &police->tcf_lock,
                                            false, est);
                if (err)
                        goto failure;
        } else if (tb[TCA_POLICE_AVRATE] &&
                   (ret == ACT_P_CREATED ||
                    !gen_estimator_active(&police->tcf_rate_est))) {
                err = -EINVAL;
                goto failure;
        }

        if (tb[TCA_POLICE_RESULT]) {
                tcfp_result = nla_get_u32(tb[TCA_POLICE_RESULT]);
                if (TC_ACT_EXT_CMP(tcfp_result, TC_ACT_GOTO_CHAIN)) {
                        NL_SET_ERR_MSG(extack,
                                       "goto chain not allowed on fallback");
                        err = -EINVAL;
                        goto failure;
                }
        }

        if ((tb[TCA_POLICE_PKTRATE64] && !tb[TCA_POLICE_PKTBURST64]) ||
            (!tb[TCA_POLICE_PKTRATE64] && tb[TCA_POLICE_PKTBURST64])) {
                NL_SET_ERR_MSG(extack,
                               "Both or neither packet-per-second burst and rate must be provided");
                err = -EINVAL;
                goto failure;
        }

        if (tb[TCA_POLICE_PKTRATE64] && R_tab) {
                NL_SET_ERR_MSG(extack,
                               "packet-per-second and byte-per-second rate limits not allowed in same action");
                err = -EINVAL;
                goto failure;
        }

        new = kzalloc_obj(*new);
        if (unlikely(!new)) {
                err = -ENOMEM;
                goto failure;
        }

        /* No failure allowed after this point */
        new->tcfp_result = tcfp_result;
        new->tcfp_mtu = parm->mtu;
        if (!new->tcfp_mtu) {
                new->tcfp_mtu = ~0;
                if (R_tab)
                        new->tcfp_mtu = 255 << R_tab->rate.cell_log;
        }
        if (R_tab) {
                new->rate_present = true;
                rate64 = nla_get_u64_default(tb[TCA_POLICE_RATE64], 0);
                psched_ratecfg_precompute(&new->rate, &R_tab->rate, rate64);
                qdisc_put_rtab(R_tab);
        } else {
                new->rate_present = false;
        }
        if (P_tab) {
                new->peak_present = true;
                prate64 = nla_get_u64_default(tb[TCA_POLICE_PEAKRATE64], 0);
                psched_ratecfg_precompute(&new->peak, &P_tab->rate, prate64);
                qdisc_put_rtab(P_tab);
        } else {
                new->peak_present = false;
        }

        new->tcfp_burst = PSCHED_TICKS2NS(parm->burst);
        if (new->peak_present)
                new->tcfp_mtu_ptoks = (s64)psched_l2t_ns(&new->peak,
                                                         new->tcfp_mtu);

        if (tb[TCA_POLICE_AVRATE])
                new->tcfp_ewma_rate = nla_get_u32(tb[TCA_POLICE_AVRATE]);

        if (tb[TCA_POLICE_PKTRATE64]) {
                pps = nla_get_u64(tb[TCA_POLICE_PKTRATE64]);
                ppsburst = nla_get_u64(tb[TCA_POLICE_PKTBURST64]);
                new->pps_present = true;
                new->tcfp_pkt_burst = PSCHED_TICKS2NS(ppsburst);
                psched_ppscfg_precompute(&new->ppsrate, pps);
        }

        new->action = parm->action;
        spin_lock_bh(&police->tcf_lock);
        spin_lock_bh(&police->tcfp_lock);
        police->tcfp_t_c = ktime_get_ns();
        police->tcfp_toks = new->tcfp_burst;
        if (new->peak_present)
                police->tcfp_ptoks = new->tcfp_mtu_ptoks;
        spin_unlock_bh(&police->tcfp_lock);
        goto_ch = tcf_action_set_ctrlact(*a, parm->action, goto_ch);
        new = rcu_replace_pointer(police->params,
                                  new,
                                  lockdep_is_held(&police->tcf_lock));
        spin_unlock_bh(&police->tcf_lock);

        if (goto_ch)
                tcf_chain_put_by_act(goto_ch);
        if (new)
                kfree_rcu(new, rcu);

        return ret;

failure:
        qdisc_put_rtab(P_tab);
        qdisc_put_rtab(R_tab);
        if (goto_ch)
                tcf_chain_put_by_act(goto_ch);
release_idr:
        tcf_idr_release(*a, bind);
        return err;
}

static bool tcf_police_mtu_check(struct sk_buff *skb, u32 limit)
{
        u32 len;

        if (skb_is_gso(skb))
                return skb_gso_validate_mac_len(skb, limit);

        len = qdisc_pkt_len(skb);
        if (skb_at_tc_ingress(skb))
                len += skb->mac_len;

        return len <= limit;
}

TC_INDIRECT_SCOPE int tcf_police_act(struct sk_buff *skb,
                                     const struct tc_action *a,
                                     struct tcf_result *res)
{
        struct tcf_police *police = to_police(a);
        s64 now, toks, ppstoks = 0, ptoks = 0;
        struct tcf_police_params *p;
        int ret;

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

        p = rcu_dereference_bh(police->params);
        ret = p->action;

        if (p->tcfp_ewma_rate) {
                struct gnet_stats_rate_est64 sample;

                if (!gen_estimator_read(&police->tcf_rate_est, &sample) ||
                    sample.bps >= p->tcfp_ewma_rate)
                        goto inc_overlimits;
        }

        if (tcf_police_mtu_check(skb, p->tcfp_mtu)) {
                if (!p->rate_present && !p->pps_present) {
                        ret = p->tcfp_result;
                        goto end;
                }

                now = ktime_get_ns();
                spin_lock_bh(&police->tcfp_lock);
                toks = min_t(s64, now - police->tcfp_t_c, p->tcfp_burst);
                if (p->peak_present) {
                        ptoks = toks + police->tcfp_ptoks;
                        if (ptoks > p->tcfp_mtu_ptoks)
                                ptoks = p->tcfp_mtu_ptoks;
                        ptoks -= (s64)psched_l2t_ns(&p->peak,
                                                    qdisc_pkt_len(skb));
                }
                if (p->rate_present) {
                        toks += police->tcfp_toks;
                        if (toks > p->tcfp_burst)
                                toks = p->tcfp_burst;
                        toks -= (s64)psched_l2t_ns(&p->rate, qdisc_pkt_len(skb));
                } else if (p->pps_present) {
                        ppstoks = min_t(s64, now - police->tcfp_t_c, p->tcfp_pkt_burst);
                        ppstoks += police->tcfp_pkttoks;
                        if (ppstoks > p->tcfp_pkt_burst)
                                ppstoks = p->tcfp_pkt_burst;
                        ppstoks -= (s64)psched_pkt2t_ns(&p->ppsrate, 1);
                }
                if ((toks | ptoks | ppstoks) >= 0) {
                        police->tcfp_t_c = now;
                        police->tcfp_toks = toks;
                        police->tcfp_ptoks = ptoks;
                        police->tcfp_pkttoks = ppstoks;
                        spin_unlock_bh(&police->tcfp_lock);
                        ret = p->tcfp_result;
                        goto inc_drops;
                }
                spin_unlock_bh(&police->tcfp_lock);
        }

inc_overlimits:
        qstats_overlimit_inc(this_cpu_ptr(police->common.cpu_qstats));
inc_drops:
        if (ret == TC_ACT_SHOT)
                qstats_drop_inc(this_cpu_ptr(police->common.cpu_qstats));
end:
        return ret;
}

static void tcf_police_cleanup(struct tc_action *a)
{
        struct tcf_police *police = to_police(a);
        struct tcf_police_params *p;

        p = rcu_dereference_protected(police->params, 1);
        if (p)
                kfree_rcu(p, rcu);
}

static void tcf_police_stats_update(struct tc_action *a,
                                    u64 bytes, u64 packets, u64 drops,
                                    u64 lastuse, bool hw)
{
        struct tcf_police *police = to_police(a);
        struct tcf_t *tm = &police->tcf_tm;

        tcf_action_update_stats(a, bytes, packets, drops, hw);
        tm->lastuse = max_t(u64, tm->lastuse, lastuse);
}

static int tcf_police_dump(struct sk_buff *skb, struct tc_action *a,
                               int bind, int ref)
{
        const struct tcf_police *police = to_police(a);
        unsigned char *b = skb_tail_pointer(skb);
        const struct tcf_police_params *p;
        struct tc_police opt = {
                .index = police->tcf_index,
                .refcnt = refcount_read(&police->tcf_refcnt) - ref,
                .bindcnt = atomic_read(&police->tcf_bindcnt) - bind,
        };
        struct tcf_t t;

        rcu_read_lock();
        p = rcu_dereference(police->params);
        opt.action = p->action;
        opt.mtu = p->tcfp_mtu;
        opt.burst = PSCHED_NS2TICKS(p->tcfp_burst);
        if (p->rate_present) {
                psched_ratecfg_getrate(&opt.rate, &p->rate);
                if ((p->rate.rate_bytes_ps >= (1ULL << 32)) &&
                    nla_put_u64_64bit(skb, TCA_POLICE_RATE64,
                                      p->rate.rate_bytes_ps,
                                      TCA_POLICE_PAD))
                        goto nla_put_failure;
        }
        if (p->peak_present) {
                psched_ratecfg_getrate(&opt.peakrate, &p->peak);
                if ((p->peak.rate_bytes_ps >= (1ULL << 32)) &&
                    nla_put_u64_64bit(skb, TCA_POLICE_PEAKRATE64,
                                      p->peak.rate_bytes_ps,
                                      TCA_POLICE_PAD))
                        goto nla_put_failure;
        }
        if (p->pps_present) {
                if (nla_put_u64_64bit(skb, TCA_POLICE_PKTRATE64,
                                      p->ppsrate.rate_pkts_ps,
                                      TCA_POLICE_PAD))
                        goto nla_put_failure;
                if (nla_put_u64_64bit(skb, TCA_POLICE_PKTBURST64,
                                      PSCHED_NS2TICKS(p->tcfp_pkt_burst),
                                      TCA_POLICE_PAD))
                        goto nla_put_failure;
        }
        if (nla_put(skb, TCA_POLICE_TBF, sizeof(opt), &opt))
                goto nla_put_failure;
        if (p->tcfp_result &&
            nla_put_u32(skb, TCA_POLICE_RESULT, p->tcfp_result))
                goto nla_put_failure;
        if (p->tcfp_ewma_rate &&
            nla_put_u32(skb, TCA_POLICE_AVRATE, p->tcfp_ewma_rate))
                goto nla_put_failure;

        tcf_tm_dump(&t, &police->tcf_tm);
        if (nla_put_64bit(skb, TCA_POLICE_TM, sizeof(t), &t, TCA_POLICE_PAD))
                goto nla_put_failure;
        rcu_read_unlock();

        return skb->len;

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

static int tcf_police_act_to_flow_act(int tc_act, u32 *extval,
                                      struct netlink_ext_ack *extack)
{
        int act_id = -EOPNOTSUPP;

        if (!TC_ACT_EXT_OPCODE(tc_act)) {
                if (tc_act == TC_ACT_OK)
                        act_id = FLOW_ACTION_ACCEPT;
                else if (tc_act ==  TC_ACT_SHOT)
                        act_id = FLOW_ACTION_DROP;
                else if (tc_act == TC_ACT_PIPE)
                        act_id = FLOW_ACTION_PIPE;
                else if (tc_act == TC_ACT_RECLASSIFY)
                        NL_SET_ERR_MSG_MOD(extack, "Offload not supported when conform/exceed action is \"reclassify\"");
                else
                        NL_SET_ERR_MSG_MOD(extack, "Unsupported conform/exceed action offload");
        } else if (TC_ACT_EXT_CMP(tc_act, TC_ACT_GOTO_CHAIN)) {
                act_id = FLOW_ACTION_GOTO;
                *extval = tc_act & TC_ACT_EXT_VAL_MASK;
        } else if (TC_ACT_EXT_CMP(tc_act, TC_ACT_JUMP)) {
                act_id = FLOW_ACTION_JUMP;
                *extval = tc_act & TC_ACT_EXT_VAL_MASK;
        } else if (tc_act == TC_ACT_UNSPEC) {
                act_id = FLOW_ACTION_CONTINUE;
        } else {
                NL_SET_ERR_MSG_MOD(extack, "Unsupported conform/exceed action offload");
        }

        return act_id;
}

static int tcf_police_offload_act_setup(struct tc_action *act, void *entry_data,
                                        u32 *index_inc, bool bind,
                                        struct netlink_ext_ack *extack)
{
        if (bind) {
                struct flow_action_entry *entry = entry_data;
                struct tcf_police *police = to_police(act);
                struct tcf_police_params *p;
                int act_id;

                p = rcu_dereference_protected(police->params,
                                              lockdep_is_held(&police->tcf_lock));

                entry->id = FLOW_ACTION_POLICE;
                entry->police.burst = tcf_police_burst(act);
                entry->police.rate_bytes_ps =
                        tcf_police_rate_bytes_ps(act);
                entry->police.peakrate_bytes_ps = tcf_police_peakrate_bytes_ps(act);
                entry->police.avrate = tcf_police_tcfp_ewma_rate(act);
                entry->police.overhead = tcf_police_rate_overhead(act);
                entry->police.burst_pkt = tcf_police_burst_pkt(act);
                entry->police.rate_pkt_ps =
                        tcf_police_rate_pkt_ps(act);
                entry->police.mtu = tcf_police_tcfp_mtu(act);

                act_id = tcf_police_act_to_flow_act(police->tcf_action,
                                                    &entry->police.exceed.extval,
                                                    extack);
                if (act_id < 0)
                        return act_id;

                entry->police.exceed.act_id = act_id;

                act_id = tcf_police_act_to_flow_act(p->tcfp_result,
                                                    &entry->police.notexceed.extval,
                                                    extack);
                if (act_id < 0)
                        return act_id;

                entry->police.notexceed.act_id = act_id;

                *index_inc = 1;
        } else {
                struct flow_offload_action *fl_action = entry_data;

                fl_action->id = FLOW_ACTION_POLICE;
        }

        return 0;
}

MODULE_AUTHOR("Alexey Kuznetsov");
MODULE_DESCRIPTION("Policing actions");
MODULE_LICENSE("GPL");

static struct tc_action_ops act_police_ops = {
        .kind           =       "police",
        .id             =       TCA_ID_POLICE,
        .owner          =       THIS_MODULE,
        .stats_update   =       tcf_police_stats_update,
        .act            =       tcf_police_act,
        .dump           =       tcf_police_dump,
        .init           =       tcf_police_init,
        .cleanup        =       tcf_police_cleanup,
        .offload_act_setup =    tcf_police_offload_act_setup,
        .size           =       sizeof(struct tcf_police),
};
MODULE_ALIAS_NET_ACT("police");

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

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

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

static struct pernet_operations police_net_ops = {
        .init = police_init_net,
        .exit_batch = police_exit_net,
        .id   = &act_police_ops.net_id,
        .size = sizeof(struct tc_action_net),
};

static int __init police_init_module(void)
{
        return tcf_register_action(&act_police_ops, &police_net_ops);
}

static void __exit police_cleanup_module(void)
{
        tcf_unregister_action(&act_police_ops, &police_net_ops);
}

module_init(police_init_module);
module_exit(police_cleanup_module);