http2_flow_control.h

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#ifndef CWIST_NET_HTTP_HTTP2_FLOW_CONTROL_H
#define CWIST_NET_HTTP_HTTP2_FLOW_CONTROL_H
 
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
 
#define CWIST_HTTP2_INITIAL_CONNECTION_WINDOW (1536U * 1024U)
#define CWIST_HTTP2_INITIAL_STREAM_WINDOW (1024U * 1024U)
#define CWIST_HTTP2_MAX_WINDOW 0x7fffffffU
 
#ifdef __cplusplus
extern "C" {
#endif
 
typedef enum cwist_http2_network_quality {
    CWIST_HTTP2_NETWORK_QUALITY_NORMAL = 0,
    CWIST_HTTP2_NETWORK_QUALITY_HIGH_RTT,
    CWIST_HTTP2_NETWORK_QUALITY_UNSTABLE
} cwist_http2_network_quality;
 
typedef struct cwist_http2_flow_control {
    uint32_t receive_window;
    uint32_t target_window;
    uint32_t min_window;
    uint32_t max_window;
    uint32_t pending_update;
    uint32_t send_window;
    uint64_t srtt_us;
    uint64_t rttvar_us;
    bool rtt_initialized;
    cwist_http2_network_quality network_quality;
    uint64_t last_window_update_us;
    uint64_t pacing_tokens;
    uint64_t pacing_rate_bytes_per_sec;
    uint64_t pacing_last_us;
} cwist_http2_flow_control;
 
typedef struct cwist_http2_stream_flow_control {
    uint32_t stream_id;
    uint32_t receive_window;
    uint32_t target_window;
    uint32_t min_window;
    uint32_t max_window;
    uint32_t pending_update;
    uint32_t send_window;
    uint64_t last_window_update_us;
} cwist_http2_stream_flow_control;
 
void cwist_http2_flow_control_init(cwist_http2_flow_control *flow_control,
                                   uint32_t initial_connection_window,
                                   uint32_t max_connection_window);
 
void cwist_http2_stream_flow_control_init(cwist_http2_stream_flow_control *flow_control,
                                          uint32_t stream_id, uint32_t initial_stream_window,
                                          uint32_t max_stream_window);
 
void cwist_http2_flow_control_update_rtt(cwist_http2_flow_control *flow_control,
                                         uint64_t rtt_sample_us);
 
bool cwist_http2_flow_control_receive(cwist_http2_flow_control *flow_control, uint32_t bytes);
 
bool cwist_http2_stream_flow_control_receive(cwist_http2_stream_flow_control *flow_control,
                                             uint32_t bytes);
 
void cwist_http2_flow_control_consume(cwist_http2_flow_control *flow_control, uint32_t bytes);
 
void cwist_http2_stream_flow_control_consume(cwist_http2_stream_flow_control *flow_control,
                                             uint32_t bytes);
 
int cwist_http2_flow_control_maybe_window_update(cwist_http2_flow_control *flow_control,
                                                 uint8_t *buffer, size_t buffer_len,
                                                 size_t *written, uint64_t now_us, bool force);
 
int cwist_http2_stream_flow_control_maybe_window_update(
    cwist_http2_flow_control *connection_flow_control,
    cwist_http2_stream_flow_control *stream_flow_control, uint8_t *buffer, size_t buffer_len,
    size_t *written, uint64_t now_us, bool force);
 
void cwist_http2_flow_control_add_send_window(cwist_http2_flow_control *flow_control,
                                              uint32_t increment);
 
void cwist_http2_stream_flow_control_add_send_window(cwist_http2_stream_flow_control *flow_control,
                                                     uint32_t increment);
 
size_t cwist_http2_flow_control_pacing_allowance(
    cwist_http2_flow_control *connection_flow_control,
    const cwist_http2_stream_flow_control *stream_flow_control, size_t requested, uint64_t now_us);
 
bool cwist_http2_flow_control_reserve_send(cwist_http2_flow_control *connection_flow_control,
                                           cwist_http2_stream_flow_control *stream_flow_control,
                                           uint32_t bytes, uint64_t now_us);
 
#ifdef __cplusplus
}
#endif
 
#endif /* CWIST_NET_HTTP_HTTP2_FLOW_CONTROL_H */