fa4e92a70a
This is the initial implementation of the ACK Manager for OpenSSL's QUIC support, with supporting design documentation and tests. Because the ACK Manager also depends on the Statistics Manager, it is also implemented here. The Statistics Manager is quite simple, so this does not amount to a large amount of extra code. Because the ACK Manager depends on a congestion controller, it adds a no-op congestion controller, which uses the previously workshopped congestion control API. Reviewed-by: Tomas Mraz <tomas@openssl.org> Reviewed-by: Richard Levitte <levitte@openssl.org> (Merged from https://github.com/openssl/openssl/pull/18676)
1.9 KiB
QUIC Statistics Manager
The statistics manager keeps track of RTT statistics for use by the QUIC implementation.
It provides the following interface:
Instantiation
The QUIC statistics manager is instantiated as follows:
typedef struct ossl_statm_st {
...
} OSSL_STATM;
int ossl_statm_init(OSSL_STATM *statm);
void ossl_statm_destroy(OSSL_STATM *statm);
The structure is defined in headers, so it may be initialised without needing
its own memory allocation. However, other code should not examine the fields of
OSSL_STATM directly.
Get RTT Info
The current RTT info is retrieved using the function ossl_statm_get_rtt_info,
which fills an OSSL_RTT_INFO structure:
typedef struct ossl_rtt_info_st {
/* As defined in RFC 9002. */
OSSL_TIME smoothed_rtt, latest_rtt, rtt_variance, min_rtt,
max_ack_delay;
} OSSL_RTT_INFO;
void ossl_statm_get_rtt_info(OSSL_STATM *statm, OSSL_RTT_INFO *rtt_info);
Update RTT
New RTT samples are provided using the ossl_statm_update_rtt function:
-
ack_delay. This is the ACK Delay value; see RFC 9000. -
override_latest_rttprovides a new latest RTT sample. If it isOSSL_TIME_ZERO, the existing Latest RTT value is used when updating the RTT.
The maximum ACK delay configured using ossl_statm_set_max_ack_delay is not
enforced automatically on the ack_delay argument as the circumstances where
this should be enforced are context sensitive. It is the caller's responsibility
to retrieve the value and enforce the maximum ACK delay if appropriate.
void ossl_statm_update_rtt(OSSL_STATM *statm,
OSSL_TIME ack_delay,
OSSL_TIME override_latest_rtt);
Set Max. Ack Delay
Sets the maximum ACK delay field reported by OSSL_RTT_INFO.
void ossl_statm_set_max_ack_delay(OSSL_STATM *statm, OSSL_TIME max_ack_delay);