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/*
* Copyright (c) 2012 Nicira Networks.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef OFPROTO_DPIF_GOVERNOR_H
#define OFPROTO_DPIF_GOVERNOR_H 1
/* Flow setup rate limiter.
*
* A governor in an engine limits a vehicle's speed. This governor limits the
* rate at which flows are set up in the datapath. The client provides as
* input the hashes of observed packets. The governor keeps track of hashes
* seen multiple times. When a given hash is seen often enough, the governor
* indicates to its client that it should set up a facet and a subfacet and a
* datapath flow for that flow.
*
* The same tracking could be done in terms of facets and subfacets directly,
* but the governor code uses much less time and space to do the same job. */
#include <stdbool.h>
#include <stdint.h>
struct governor {
char *name; /* Name, for log messages. */
uint8_t *table; /* Table of counters, two per byte. */
unsigned int size; /* Table size in bytes. */
long long int start; /* Time when the table was last cleared. */
unsigned int n_packets; /* Number of packets processed. */
};
struct governor *governor_create(const char *name);
void governor_destroy(struct governor *);
void governor_run(struct governor *);
void governor_wait(struct governor *);
bool governor_is_idle(struct governor *);
bool governor_should_install_flow(struct governor *, uint32_t hash, int n);
#endif /* ofproto/ofproto-dpif-governor.h */
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