forked from cory/tildefriends
298 lines
11 KiB
C
298 lines
11 KiB
C
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/*
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* Copyright 2022-2023 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the Apache License 2.0 (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#ifndef OSSL_QUIC_ACKM_H
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# define OSSL_QUIC_ACKM_H
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# include "internal/quic_statm.h"
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# include "internal/quic_cc.h"
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# include "internal/quic_types.h"
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# include "internal/quic_wire.h"
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# include "internal/time.h"
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# include "internal/list.h"
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# ifndef OPENSSL_NO_QUIC
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typedef struct ossl_ackm_st OSSL_ACKM;
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OSSL_ACKM *ossl_ackm_new(OSSL_TIME (*now)(void *arg),
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void *now_arg,
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OSSL_STATM *statm,
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const OSSL_CC_METHOD *cc_method,
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OSSL_CC_DATA *cc_data);
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void ossl_ackm_free(OSSL_ACKM *ackm);
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void ossl_ackm_set_loss_detection_deadline_callback(OSSL_ACKM *ackm,
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void (*fn)(OSSL_TIME deadline,
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void *arg),
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void *arg);
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void ossl_ackm_set_ack_deadline_callback(OSSL_ACKM *ackm,
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void (*fn)(OSSL_TIME deadline,
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int pkt_space,
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void *arg),
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void *arg);
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/*
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* Configures the RX-side maximum ACK delay. This is the maximum amount of time
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* the peer is allowed to delay sending an ACK frame after receiving an
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* ACK-eliciting packet. The peer communicates this value via a transport
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* parameter and it must be provided to the ACKM.
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*/
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void ossl_ackm_set_rx_max_ack_delay(OSSL_ACKM *ackm, OSSL_TIME rx_max_ack_delay);
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/*
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* Configures the TX-side maximum ACK delay. This is the maximum amount of time
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* we are allowed to delay sending an ACK frame after receiving an ACK-eliciting
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* packet. Note that this cannot be changed after a connection is established as
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* it must be accurately reported in the transport parameters we send to our
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* peer.
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*/
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void ossl_ackm_set_tx_max_ack_delay(OSSL_ACKM *ackm, OSSL_TIME tx_max_ack_delay);
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typedef struct ossl_ackm_tx_pkt_st OSSL_ACKM_TX_PKT;
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struct ossl_ackm_tx_pkt_st {
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/* The packet number of the transmitted packet. */
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QUIC_PN pkt_num;
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/* The number of bytes in the packet which was sent. */
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size_t num_bytes;
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/* The time at which the packet was sent. */
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OSSL_TIME time;
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/*
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* If the packet being described by this structure contains an ACK frame,
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* this must be set to the largest PN ACK'd by that frame.
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*
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* Otherwise, it should be set to QUIC_PN_INVALID.
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*
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* This is necessary to bound the number of PNs we have to keep track of on
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* the RX side (RFC 9000 s. 13.2.4). It allows older PN tracking information
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* on the RX side to be discarded.
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*/
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QUIC_PN largest_acked;
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/*
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* One of the QUIC_PN_SPACE_* values. This qualifies the pkt_num field
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* into a packet number space.
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*/
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unsigned int pkt_space :2;
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/*
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* 1 if the packet is in flight. A packet is considered 'in flight' if it is
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* counted for purposes of congestion control and 'bytes in flight' counts.
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* Most packets are considered in flight. The only circumstance where a
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* numbered packet is not considered in flight is if it contains only ACK
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* frames (not even PADDING frames), as these frames can bypass CC.
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*/
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unsigned int is_inflight :1;
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/*
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* 1 if the packet has one or more ACK-eliciting frames.
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* Note that if this is set, is_inflight must be set.
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*/
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unsigned int is_ack_eliciting :1;
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/* 1 if the packet is a PTO probe. */
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unsigned int is_pto_probe :1;
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/* 1 if the packet is an MTU probe. */
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unsigned int is_mtu_probe :1;
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/* Callback called if frames in this packet are lost. arg is cb_arg. */
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void (*on_lost)(void *arg);
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/* Callback called if frames in this packet are acked. arg is cb_arg. */
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void (*on_acked)(void *arg);
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/*
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* Callback called if frames in this packet are neither acked nor lost. arg
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* is cb_arg.
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*/
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void (*on_discarded)(void *arg);
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void *cb_arg;
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/*
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* (Internal use fields; must be zero-initialized.)
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*
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* Keep a TX history list, anext is used to manifest
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* a singly-linked list of newly-acknowledged packets, and lnext is used to
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* manifest a singly-linked list of newly lost packets.
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*/
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OSSL_LIST_MEMBER(tx_history, OSSL_ACKM_TX_PKT);
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struct ossl_ackm_tx_pkt_st *anext;
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struct ossl_ackm_tx_pkt_st *lnext;
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};
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int ossl_ackm_on_tx_packet(OSSL_ACKM *ackm, OSSL_ACKM_TX_PKT *pkt);
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int ossl_ackm_on_rx_datagram(OSSL_ACKM *ackm, size_t num_bytes);
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# define OSSL_ACKM_ECN_NONE 0
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# define OSSL_ACKM_ECN_ECT1 1
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# define OSSL_ACKM_ECN_ECT0 2
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# define OSSL_ACKM_ECN_ECNCE 3
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typedef struct ossl_ackm_rx_pkt_st {
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/* The packet number of the received packet. */
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QUIC_PN pkt_num;
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/* The time at which the packet was received. */
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OSSL_TIME time;
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/*
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* One of the QUIC_PN_SPACE_* values. This qualifies the pkt_num field
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* into a packet number space.
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*/
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unsigned int pkt_space :2;
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/* 1 if the packet has one or more ACK-eliciting frames. */
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unsigned int is_ack_eliciting :1;
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/*
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* One of the OSSL_ACKM_ECN_* values. This is the ECN labelling applied to
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* the received packet. If unknown, use OSSL_ACKM_ECN_NONE.
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*/
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unsigned int ecn :2;
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} OSSL_ACKM_RX_PKT;
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int ossl_ackm_on_rx_packet(OSSL_ACKM *ackm, const OSSL_ACKM_RX_PKT *pkt);
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int ossl_ackm_on_rx_ack_frame(OSSL_ACKM *ackm, const OSSL_QUIC_FRAME_ACK *ack,
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int pkt_space, OSSL_TIME rx_time);
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/*
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* Discards a PN space. This must be called for a PN space before freeing the
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* ACKM if you want in-flight packets to have their discarded callbacks called.
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* This should never be called in ordinary QUIC usage for the Application Data
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* PN space, but it may be called for the Application Data PN space prior to
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* freeing the ACKM to simplify teardown implementations.
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*/
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int ossl_ackm_on_pkt_space_discarded(OSSL_ACKM *ackm, int pkt_space);
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int ossl_ackm_on_handshake_confirmed(OSSL_ACKM *ackm);
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int ossl_ackm_on_timeout(OSSL_ACKM *ackm);
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OSSL_TIME ossl_ackm_get_loss_detection_deadline(OSSL_ACKM *ackm);
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/*
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* Generates an ACK frame, regardless of whether the ACK manager thinks
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* one should currently be sent.
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*
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* This clears the flag returned by ossl_ackm_is_ack_desired and the deadline
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* returned by ossl_ackm_get_ack_deadline.
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*/
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const OSSL_QUIC_FRAME_ACK *ossl_ackm_get_ack_frame(OSSL_ACKM *ackm,
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int pkt_space);
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/*
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* Returns the deadline after which an ACK frame should be generated by calling
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* ossl_ackm_get_ack_frame, or OSSL_TIME_INFINITY if no deadline is currently
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* applicable. If the deadline has already passed, this function may return that
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* deadline, or may return OSSL_TIME_ZERO.
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*/
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OSSL_TIME ossl_ackm_get_ack_deadline(OSSL_ACKM *ackm, int pkt_space);
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/*
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* Returns 1 if the ACK manager thinks an ACK frame ought to be generated and
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* sent at this time. ossl_ackm_get_ack_frame will always provide an ACK frame
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* whether or not this returns 1, so it is suggested that you call this function
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* first to determine whether you need to generate an ACK frame.
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*
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* The return value of this function can change based on calls to
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* ossl_ackm_on_rx_packet and based on the passage of time (see
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* ossl_ackm_get_ack_deadline).
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*/
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int ossl_ackm_is_ack_desired(OSSL_ACKM *ackm, int pkt_space);
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/*
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* Returns 1 if the given RX PN is 'processable'. A processable PN is one that
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* is not either
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*
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* - duplicate, meaning that we have already been passed such a PN in a call
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* to ossl_ackm_on_rx_packet; or
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*
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* - written off, meaning that the PN is so old we have stopped tracking state
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* for it (meaning that we cannot tell whether it is a duplicate and cannot
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* process it safely).
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*
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* This should be called for a packet before attempting to process its contents.
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* Failure to do so may result in processing a duplicated packet in violation of
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* the RFC.
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*
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* The return value of this function transitions from 1 to 0 for a given PN once
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* that PN is passed to ossl_ackm_on_rx_packet, thus this function must be used
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* before calling ossl_ackm_on_rx_packet.
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*/
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int ossl_ackm_is_rx_pn_processable(OSSL_ACKM *ackm, QUIC_PN pn, int pkt_space);
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typedef struct ossl_ackm_probe_info_st {
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/*
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* The following two probe request types are used only for anti-deadlock
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* purposes in relation to the anti-amplification logic, by generating
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* packets to buy ourselves more anti-amplification credit with the server
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* until a client address is verified. Note that like all Initial packets,
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* any Initial probes are padded.
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*
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* Note: The ACKM will only ever increase these by one at a time,
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* as only one probe packet should be generated for these cases.
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*/
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uint32_t anti_deadlock_initial, anti_deadlock_handshake;
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/*
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* Send an ACK-eliciting packet for each count here.
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*
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* Note: The ACKM may increase this by either one or two for each probe
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* request, depending on how many probe packets it thinks should be
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* generated.
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*/
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uint32_t pto[QUIC_PN_SPACE_NUM];
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} OSSL_ACKM_PROBE_INFO;
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/*
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* Returns a pointer to a structure counting any pending probe requests which
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* have been generated by the ACKM. The fields in the structure are incremented
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* by one every time the ACKM wants another probe of the given type to be sent.
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* If the ACKM thinks two packets should be generated for a probe, it will
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* increment the field twice.
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*
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* It is permissible for the caller to decrement or zero these fields to keep
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* track of when it has generated a probe as asked. The returned structure
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* has the same lifetime as the ACKM.
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*
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* This function should be called after calling e.g. ossl_ackm_on_timeout
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* to determine if any probe requests have been generated.
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*/
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OSSL_ACKM_PROBE_INFO *ossl_ackm_get0_probe_request(OSSL_ACKM *ackm);
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int ossl_ackm_get_largest_unacked(OSSL_ACKM *ackm, int pkt_space, QUIC_PN *pn);
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/*
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* Forces the ACKM to consider a packet with the given PN in the given PN space
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* as having been pseudo-lost. The main reason to use this is during a Retry, to
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* force any resources sent in the first Initial packet to be resent.
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*
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* The lost callback is called for the packet, but the packet is NOT considered
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* lost for congestion control purposes. Thus this is not exactly the same as a
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* true loss situation.
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*/
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int ossl_ackm_mark_packet_pseudo_lost(OSSL_ACKM *ackm,
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int pkt_space, QUIC_PN pn);
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/*
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* Returns the PTO duration as currently calculated. This is a quantity of time.
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* This duration is used in various parts of QUIC besides the ACKM.
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*/
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OSSL_TIME ossl_ackm_get_pto_duration(OSSL_ACKM *ackm);
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/* Returns the largest acked PN in the given PN space. */
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QUIC_PN ossl_ackm_get_largest_acked(OSSL_ACKM *ackm, int pkt_space);
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# endif
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#endif
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