net/sched: act_police: add support for packet-per-second policing

Allow a policer action to enforce a rate-limit based on packets-per-second,
configurable using a packet-per-second rate and burst parameters.

e.g.
tc filter add dev tap1 parent ffff: u32 match \
        u32 0 0 police pkts_rate 3000 pkts_burst 1000

Testing was unable to uncover a performance impact of this change on
existing features.

Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Louis Peens <louis.peens@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/sch_generic.h

@@ -1242,6 +1242,20 @@ static inline void psched_ratecfg_getrate(struct tc_ratespec *res,
 	res->linklayer = (r->linklayer & TC_LINKLAYER_MASK);
 }
 
+struct psched_pktrate {
+	u64	rate_pkts_ps; /* packets per second */
+	u32	mult;
+	u8	shift;
+};
+
+static inline u64 psched_pkt2t_ns(const struct psched_pktrate *r,
+				  unsigned int pkt_num)
+{
+	return ((u64)pkt_num * r->mult) >> r->shift;
+}
+
+void psched_ppscfg_precompute(struct psched_pktrate *r, u64 pktrate64);
+
 /* Mini Qdisc serves for specific needs of ingress/clsact Qdisc.
  * The fast path only needs to access filter list and to update stats
  */

include/net/tc_act/tc_police.h

@@ -10,10 +10,13 @@ struct tcf_police_params {
 	s64			tcfp_burst;
 	u32			tcfp_mtu;
 	s64			tcfp_mtu_ptoks;
+	s64			tcfp_pkt_burst;
 	struct psched_ratecfg	rate;
 	bool			rate_present;
 	struct psched_ratecfg	peak;
 	bool			peak_present;
+	struct psched_pktrate	ppsrate;
+	bool			pps_present;
 	struct rcu_head rcu;
 };
 
@@ -24,6 +27,7 @@ struct tcf_police {
 	spinlock_t		tcfp_lock ____cacheline_aligned_in_smp;
 	s64			tcfp_toks;
 	s64			tcfp_ptoks;
+	s64			tcfp_pkttoks;
 	s64			tcfp_t_c;
 };
 
@@ -99,14 +103,50 @@ static inline u32 tcf_police_burst(const struct tc_action *act)
 
 static inline u64 tcf_police_rate_pkt_ps(const struct tc_action *act)
 {
-	/* Not implemented */
-	return 0;
+	struct tcf_police *police = to_police(act);
+	struct tcf_police_params *params;
+
+	params = rcu_dereference_protected(police->params,
+					   lockdep_is_held(&police->tcf_lock));
+	return params->ppsrate.rate_pkts_ps;
 }
 
 static inline u32 tcf_police_burst_pkt(const struct tc_action *act)
 {
-	/* Not implemented */
-	return 0;
+	struct tcf_police *police = to_police(act);
+	struct tcf_police_params *params;
+	u32 burst;
+
+	params = rcu_dereference_protected(police->params,
+					   lockdep_is_held(&police->tcf_lock));
+
+	/*
+	 *  "rate" pkts     "burst" nanoseconds
+	 *  ------------ *  -------------------
+	 *    1 second          2^6 ticks
+	 *
+	 * ------------------------------------
+	 *        NSEC_PER_SEC nanoseconds
+	 *        ------------------------
+	 *              2^6 ticks
+	 *
+	 *    "rate" pkts    "burst" nanoseconds            2^6 ticks
+	 *  = ------------ * ------------------- * ------------------------
+	 *      1 second          2^6 ticks        NSEC_PER_SEC nanoseconds
+	 *
+	 *   "rate" * "burst"
+	 * = ---------------- pkts/nanosecond
+	 *    NSEC_PER_SEC^2
+	 *
+	 *
+	 *   "rate" * "burst"
+	 * = ---------------- pkts/second
+	 *     NSEC_PER_SEC
+	 */
+	burst = div_u64(params->tcfp_pkt_burst * params->ppsrate.rate_pkts_ps,
+			NSEC_PER_SEC);
+
+	return burst;
 }
 
 static inline u32 tcf_police_tcfp_mtu(const struct tc_action *act)

include/uapi/linux/pkt_cls.h

@@ -190,6 +190,8 @@ enum {
 	TCA_POLICE_PAD,
 	TCA_POLICE_RATE64,
 	TCA_POLICE_PEAKRATE64,
+	TCA_POLICE_PKTRATE64,
+	TCA_POLICE_PKTBURST64,
 	__TCA_POLICE_MAX
 #define TCA_POLICE_RESULT TCA_POLICE_RESULT
 };