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/*
* Copyright 2022 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#ifndef OSSL_QUIC_CC_H
# define OSSL_QUIC_CC_H
#include "openssl/params.h"
#include "internal/time.h"
typedef struct ossl_cc_data_st *OSSL_CC_DATA;
typedef struct ossl_cc_method_st {
void *dummy;
/*
* Create a new OSSL_CC_DATA object to handle the congestion control
* calculations.
*
* |settings| are mandatory settings that will cause the
* new() call to fail if they are not understood).
* |options| are optional settings that will not
* cause the new() call to fail if they are not understood.
* |changeables| contain additional parameters that the congestion
* control algorithms need that can be updated during the
* connection lifetime - for example size of the datagram payload.
* To avoid calling a function with OSSL_PARAM array every time
* these parameters are changed the addresses of these param
* values are considered permanent and the values can be updated
* any time.
*/
OSSL_CC_DATA *(*new)(OSSL_PARAM *settings, OSSL_PARAM *options,
OSSL_PARAM *changeables);
/*
* Release the OSSL_CC_DATA.
*/
void (*free)(OSSL_CC_DATA *ccdata);
/*
* Reset the congestion control state.
* |flags| to support different level of reset (partial/full).
*/
void (*reset)(OSSL_CC_DATA *ccdata, int flags);
/*
* Set number of packets exempted from CC - used for probing
* |numpackets| is a small value (2).
* Returns 0 on error, 1 otherwise.
*/
int (*set_exemption)(OSSL_CC_DATA *ccdata, int numpackets);
/*
* Get current number of packets exempted from CC.
* Returns negative value on error, the number otherwise.
*/
int (*get_exemption)(OSSL_CC_DATA *ccdata);
/*
* Returns 1 if sending is allowed, 0 otherwise.
*/
int (*can_send)(OSSL_CC_DATA *ccdata);
/*
* Returns number of bytes allowed to be sent.
* |time_since_last_send| is time since last send operation
* in microseconds.
* |time_valid| is 1 if the |time_since_last_send| holds
* a meaningful value, 0 otherwise.
*/
uint64_t (*get_send_allowance)(OSSL_CC_DATA *ccdata,
OSSL_TIME time_since_last_send,
int time_valid);
/*
* Returns the maximum number of bytes allowed to be in flight.
*/
uint64_t (*get_bytes_in_flight_max)(OSSL_CC_DATA *ccdata);
/*
* Returns the time at which the CC will next release more budget
* for sending, or ossl_time_infinite().
*/
OSSL_TIME (*get_next_credit_time)(OSSL_CC_DATA *ccdata);
/*
* To be called when a packet with retransmittable data was sent.
* |num_retransmittable_bytes| is the number of bytes sent
* in the packet that are retransmittable.
* Returns 1 on success, 0 otherwise.
*/
int (*on_data_sent)(OSSL_CC_DATA *ccdata,
uint64_t num_retransmittable_bytes);
/*
* To be called when retransmittable data was invalidated.
* I.E. they are not considered in-flight anymore but
* are neither acknowledged nor lost. In particular used when
* 0RTT data was rejected.
* |num_retransmittable_bytes| is the number of bytes
* of the invalidated data.
* Returns 1 if sending is unblocked (can_send returns 1), 0
* otherwise.
*/
int (*on_data_invalidated)(OSSL_CC_DATA *ccdata,
uint64_t num_retransmittable_bytes);
/*
* To be called when sent data was acked.
* |time_now| is current time in microseconds.
* |largest_pn_acked| is the largest packet number of the acked
* packets.
* |num_retransmittable_bytes| is the number of retransmittable
* packet bytes that were newly acked.
* Returns 1 if sending is unblocked (can_send returns 1), 0
* otherwise.
*/
int (*on_data_acked)(OSSL_CC_DATA *ccdata,
OSSL_TIME time_now,
uint64_t last_pn_acked,
uint64_t num_retransmittable_bytes);
/*
* To be called when sent data is considered lost.
* |largest_pn_lost| is the largest packet number of the lost
* packets.
* |largest_pn_sent| is the largest packet number sent on this
* connection.
* |num_retransmittable_bytes| is the number of retransmittable
* packet bytes that are newly considered lost.
* |persistent_congestion| is 1 if the congestion is considered
* persistent (see RFC 9002 Section 7.6), 0 otherwise.
*/
void (*on_data_lost)(OSSL_CC_DATA *ccdata,
uint64_t largest_pn_lost,
uint64_t largest_pn_sent,
uint64_t num_retransmittable_bytes,
int persistent_congestion);
/*
* To be called when all lost data from the previous call to
* on_data_lost() was actually acknowledged.
* This reverts the size of the congestion window to the state
* before the on_data_lost() call.
* Returns 1 if sending is unblocked, 0 otherwise.
*/
int (*on_spurious_congestion_event)(OSSL_CC_DATA *ccdata);
} OSSL_CC_METHOD;
extern const OSSL_CC_METHOD ossl_cc_dummy_method;
#endif
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