tildefriends/deps/openssl/mingw64/usr/local/include/internal/quic_fc.h
2023-11-25 17:32:12 +00:00

278 lines
10 KiB
C

/*
* Copyright 2022-2023 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_FC_H
# define OSSL_QUIC_FC_H
# include <openssl/ssl.h>
# include "internal/time.h"
# ifndef OPENSSL_NO_QUIC
/*
* TX Flow Controller (TXFC)
* =========================
*
* For discussion, see doc/designs/quic-design/quic-fc.md.
*/
typedef struct quic_txfc_st QUIC_TXFC;
struct quic_txfc_st {
QUIC_TXFC *parent; /* stream-level iff non-NULL */
uint64_t swm, cwm;
char has_become_blocked;
};
/*
* Initialises a TX flow controller. conn_txfc should be non-NULL and point to
* the connection-level flow controller if the TXFC is for stream-level flow
* control, and NULL otherwise.
*/
int ossl_quic_txfc_init(QUIC_TXFC *txfc, QUIC_TXFC *conn_txfc);
/*
* Gets the parent (i.e., connection-level) TX flow controller. Returns NULL if
* called on a connection-level TX flow controller.
*/
QUIC_TXFC *ossl_quic_txfc_get_parent(QUIC_TXFC *txfc);
/*
* Bump the credit watermark (CWM) value. This is the 'On TX Window Updated'
* operation. This function is a no-op if it has already been called with an
* equal or higher CWM value.
*
* It returns 1 iff the call resulted in the CWM being bumped and 0 if it was
* not increased because it has already been called with an equal or higher CWM
* value. This is not an error per se but may indicate a local programming error
* or a protocol error in a remote peer.
*/
int ossl_quic_txfc_bump_cwm(QUIC_TXFC *txfc, uint64_t cwm);
/*
* Get the number of bytes by which we are in credit. This is the number of
* controlled bytes we are allowed to send. (Thus if this function returns 0, we
* are currently blocked.)
*
* If called on a stream-level TXFC, ossl_quic_txfc_get_credit is called on
* the connection-level TXFC as well, and the lesser of the two values is
* returned. The consumed value is the amount already consumed on the connection
* level TXFC.
*/
uint64_t ossl_quic_txfc_get_credit(QUIC_TXFC *txfc, uint64_t consumed);
/*
* Like ossl_quic_txfc_get_credit(), but when called on a stream-level TXFC,
* retrieves only the stream-level credit value and does not clamp it based on
* connection-level flow control. Any credit value is reduced by the consumed
* amount.
*/
uint64_t ossl_quic_txfc_get_credit_local(QUIC_TXFC *txfc, uint64_t consumed);
/*
* Consume num_bytes of credit. This is the 'On TX' operation. This should be
* called when we transmit any controlled bytes. Calling this with an argument
* of 0 is a no-op.
*
* We must never transmit more controlled bytes than we are in credit for (see
* the return value of ossl_quic_txfc_get_credit()). If you call this function
* with num_bytes greater than our current credit, this function consumes the
* remainder of the credit and returns 0. This indicates a serious programming
* error on the caller's part. Otherwise, the function returns 1.
*
* If called on a stream-level TXFC, ossl_quic_txfc_consume_credit() is called
* on the connection-level TXFC also. If the call to that function on the
* connection-level TXFC returns zero, this function will also return zero.
*/
int ossl_quic_txfc_consume_credit(QUIC_TXFC *txfc, uint64_t num_bytes);
/*
* Like ossl_quic_txfc_consume_credit(), but when called on a stream-level TXFC,
* consumes only from the stream-level credit and does not inform the
* connection-level TXFC.
*/
int ossl_quic_txfc_consume_credit_local(QUIC_TXFC *txfc, uint64_t num_bytes);
/*
* This flag is provided for convenience. A caller is not required to use it. It
* is a boolean flag set whenever our credit drops to zero. If clear is 1, the
* flag is cleared. The old value of the flag is returned. Callers may use this
* to determine if they need to send a DATA_BLOCKED or STREAM_DATA_BLOCKED
* frame, which should contain the value returned by ossl_quic_txfc_get_cwm().
*/
int ossl_quic_txfc_has_become_blocked(QUIC_TXFC *txfc, int clear);
/*
* Get the current CWM value. This is mainly only needed when generating a
* DATA_BLOCKED or STREAM_DATA_BLOCKED frame, or for diagnostic purposes.
*/
uint64_t ossl_quic_txfc_get_cwm(QUIC_TXFC *txfc);
/*
* Get the current spent watermark (SWM) value. This is purely for diagnostic
* use and should not be needed in normal circumstances.
*/
uint64_t ossl_quic_txfc_get_swm(QUIC_TXFC *txfc);
/*
* RX Flow Controller (RXFC)
* =========================
*/
typedef struct quic_rxfc_st QUIC_RXFC;
struct quic_rxfc_st {
/*
* swm is the sent/received watermark, which tracks how much we have
* received from the peer. rwm is the retired watermark, which tracks how
* much has been passed to the application. esrwm is the rwm value at which
* the current auto-tuning epoch started. hwm is the highest stream length
* (STREAM frame offset + payload length) we have seen from a STREAM frame
* yet.
*/
uint64_t cwm, swm, rwm, esrwm, hwm, cur_window_size, max_window_size;
OSSL_TIME epoch_start;
OSSL_TIME (*now)(void *arg);
void *now_arg;
QUIC_RXFC *parent;
unsigned char error_code, has_cwm_changed, is_fin, standalone;
};
/*
* Initialises an RX flow controller. conn_rxfc should be non-NULL and point to
* a connection-level RXFC if the RXFC is for stream-level flow control, and
* NULL otherwise. initial_window_size and max_window_size specify the initial
* and absolute maximum window sizes, respectively. Window size values are
* expressed in bytes and determine how much credit the RXFC extends to the peer
* to transmit more data at a time.
*/
int ossl_quic_rxfc_init(QUIC_RXFC *rxfc, QUIC_RXFC *conn_rxfc,
uint64_t initial_window_size,
uint64_t max_window_size,
OSSL_TIME (*now)(void *arg),
void *now_arg);
/*
* Initialises an RX flow controller which is used by itself and not under a
* connection-level RX flow controller. This can be used for stream count
* enforcement as well as CRYPTO buffer enforcement.
*/
int ossl_quic_rxfc_init_standalone(QUIC_RXFC *rxfc,
uint64_t initial_window_size,
OSSL_TIME (*now)(void *arg),
void *now_arg);
/*
* Gets the parent (i.e., connection-level) RXFC. Returns NULL if called on a
* connection-level RXFC.
*/
QUIC_RXFC *ossl_quic_rxfc_get_parent(QUIC_RXFC *rxfc);
/*
* Changes the current maximum window size value.
*/
void ossl_quic_rxfc_set_max_window_size(QUIC_RXFC *rxfc,
size_t max_window_size);
/*
* To be called whenever a STREAM frame is received.
*
* end is the value (offset + len), where offset is the offset field of the
* STREAM frame and len is the length of the STREAM frame's payload in bytes.
*
* is_fin should be 1 if the STREAM frame had the FIN flag set and 0 otherwise.
*
* This function may be used on a stream-level RXFC only. The connection-level
* RXFC will have its state updated by the stream-level RXFC.
*
* You should check ossl_quic_rxfc_has_error() on both connection-level and
* stream-level RXFCs after calling this function, as an incoming STREAM frame
* may cause flow control limits to be exceeded by an errant peer. This
* function still returns 1 in this case, as this is not a caller error.
*
* Returns 1 on success or 0 on failure.
*/
int ossl_quic_rxfc_on_rx_stream_frame(QUIC_RXFC *rxfc,
uint64_t end, int is_fin);
/*
* To be called whenever controlled bytes are retired, i.e. when bytes are
* dequeued from a QUIC stream and passed to the application. num_bytes
* is the number of bytes which were passed to the application.
*
* You should call this only on a stream-level RXFC. This function will update
* the connection-level RXFC automatically.
*
* rtt should be the current best understanding of the RTT to the peer, as
* offered by the Statistics Manager.
*
* You should check ossl_quic_rxfc_has_cwm_changed() after calling this
* function, as it may have caused the RXFC to decide to grant more flow control
* credit to the peer.
*
* Returns 1 on success and 0 on failure.
*/
int ossl_quic_rxfc_on_retire(QUIC_RXFC *rxfc,
uint64_t num_bytes,
OSSL_TIME rtt);
/*
* Returns the current CWM which the RXFC thinks the peer should have.
*
* Note that the RXFC will increase this value in response to events, at which
* time a MAX_DATA or MAX_STREAM_DATA frame must be generated. Use
* ossl_quic_rxfc_has_cwm_changed() to detect this condition.
*
* This value increases monotonically.
*/
uint64_t ossl_quic_rxfc_get_cwm(QUIC_RXFC *rxfc);
/*
* Returns the current SWM. This is the total number of bytes the peer has
* transmitted to us. This is intended for diagnostic use only; you should
* not need it.
*/
uint64_t ossl_quic_rxfc_get_swm(QUIC_RXFC *rxfc);
/*
* Returns the current RWM. This is the total number of bytes that has been
* retired. This is intended for diagnostic use only; you should not need it.
*/
uint64_t ossl_quic_rxfc_get_rwm(QUIC_RXFC *rxfc);
/*
* Returns the CWM changed flag. If clear is 1, the flag is cleared and the old
* value is returned.
*/
int ossl_quic_rxfc_has_cwm_changed(QUIC_RXFC *rxfc, int clear);
/*
* Returns a QUIC_ERR_* error code if a flow control error has been detected.
* Otherwise, returns QUIC_ERR_NO_ERROR. If clear is 1, the error is cleared
* and the old value is returned.
*
* May return one of the following values:
*
* QUIC_ERR_FLOW_CONTROL_ERROR:
* This indicates a flow control protocol violation by the remote peer; the
* connection should be terminated in this event.
* QUIC_ERR_FINAL_SIZE:
* The peer attempted to change the stream length after ending the stream.
*/
int ossl_quic_rxfc_get_error(QUIC_RXFC *rxfc, int clear);
/*
* Returns 1 if the RXFC is a stream-level RXFC and the RXFC knows the final
* size for the stream in bytes. If this is the case and final_size is non-NULL,
* writes the final size to *final_size. Otherwise, returns 0.
*/
int ossl_quic_rxfc_get_final_size(const QUIC_RXFC *rxfc, uint64_t *final_size);
# endif
#endif