/*
 * include/haproxy/xprt_quic-t.h
 * This file contains applet function prototypes
 *
 * Copyright 2019 HAProxy Technologies, Frédéric Lécaille <flecaille@haproxy.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation, version 2.1
 * exclusively.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifndef _HAPROXY_XPRT_QUIC_T_H
#define _HAPROXY_XPRT_QUIC_T_H
#ifdef USE_QUIC
#ifndef USE_OPENSSL
#error "Must define USE_OPENSSL"
#endif

#include <sys/socket.h>
#include <openssl/ssl.h>

#include <haproxy/cbuf-t.h>
#include <haproxy/list.h>

#include <haproxy/mux_quic-t.h>
#include <haproxy/quic_cc-t.h>
#include <haproxy/quic_frame-t.h>
#include <haproxy/quic_tls-t.h>
#include <haproxy/quic_loss-t.h>
#include <haproxy/task.h>

#include <import/ebtree-t.h>

typedef unsigned long long ull;

#define QUIC_PROTOCOL_VERSION_DRAFT_28   0xff00001c /* draft-28 */
#define QUIC_PROTOCOL_VERSION_DRAFT_29   0xff00001d /* draft-29 */
#define QUIC_PROTOCOL_VERSION_1          0x00000001 /* V1 */

#define QUIC_INITIAL_IPV4_MTU      1252 /* (bytes) */
#define QUIC_INITIAL_IPV6_MTU      1232
/* XXX TO DO XXX */
/* Maximum packet length during handshake */
#define QUIC_PACKET_MAXLEN     2048

/* The minimum length of Initial packets. */
#define QUIC_INITIAL_PACKET_MINLEN 1200

/* Lengths of the QUIC CIDs generated by the haproxy implementation. */
#define QUIC_HAP_CID_LEN               8

/* Common definitions for short and long QUIC packet headers. */
/* QUIC connection ID maximum length for version 1. */
#define QUIC_CID_MAXLEN               20 /* bytes */
/*
 * All QUIC packets with long headers are made of at least (in bytes):
 * flags(1), version(4), DCID length(1), DCID(0..20), SCID length(1), SCID(0..20)
 */
#define QUIC_LONG_PACKET_MINLEN            7
/*
 * All QUIC packets with short headers are made of at least (in bytes):
 * flags(1), DCID(0..20)
 */
#define QUIC_SHORT_PACKET_MINLEN           1
/* Byte 0 of QUIC packets. */
#define QUIC_PACKET_LONG_HEADER_BIT  0x80 /* Long header format if set, short if not. */
#define QUIC_PACKET_FIXED_BIT        0x40 /* Must always be set for all the headers. */

/*
 *  0                   1                   2                   3
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+
 * |1|1|T|T|X|X|X|X|
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                         Version (32)                          |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * | DCID Len (8)  |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |               Destination Connection ID (0..160)            ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * | SCID Len (8)  |
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                 Source Connection ID (0..160)               ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *                      Long Header Packet Format
 */

/* Two bits (T) for QUIC packet types. */
#define QUIC_PACKET_TYPE_BITMASK     0x03
#define QUIC_PACKET_TYPE_SHIFT       4

enum quic_pkt_type {
	QUIC_PACKET_TYPE_INITIAL,
	QUIC_PACKET_TYPE_0RTT,
	QUIC_PACKET_TYPE_HANDSHAKE,
	QUIC_PACKET_TYPE_RETRY,
	/*
	 * The following one is not defined by the RFC but we define it for our
	 * own convenience.
	 */
	QUIC_PACKET_TYPE_SHORT,
};

/* Packet number field length. */
#define QUIC_PACKET_PNL_BITMASK      0x03
#define QUIC_PACKET_PN_MAXLEN        4

/*
 *  0                   1                   2                   3
 *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 * +-+-+-+-+-+-+-+-+
 * |0|1|S|R|R|K|P|P|
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                Destination Connection ID (0..160)           ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                     Packet Number (8/16/24/32)              ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 * |                     Protected Payload (*)                   ...
 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 *                      Short Header Packet Format
 */

/* Bit (S) of short header. */
#define QUIC_PACKET_SPIN_BIT         0x20

/* Reserved Bits (R):  The next two bits of byte 0 are reserved.
 * These bits are protected using header protection
 * (see Section 5.4 of [QUIC-TLS]). The value included
 * prior to protection MUST be set to 0. An endpoint MUST treat
 * receipt of a packet that has a non-zero value for these bits,
 * after removing both packet and header protection, as a connection
 * error of type PROTOCOL_VIOLATION. Discarding such a packet after
 * only removing header protection can expose the endpoint to attacks
 * (see Section 9.3 of [QUIC-TLS]).
 */
#define QUIC_PACKET_RESERVED_BITS    0x18 /* (protected) */

#define QUIC_PACKET_KEY_PHASE_BIT    0x04 /* (protected) */

/*
 * Transport level error codes.
 */
#define QC_ERR_NO_ERROR                     0x00
#define QC_ERR_INTERNAL_ERROR               0x01
#define QC_ERR_CONNECTION_REFUSED           0x02
#define QC_ERR_FLOW_CONTROL_ERROR           0x03
#define QC_ERR_STREAM_LIMIT_ERROR           0x04
#define QC_ERR_STREAM_STATE_ERROR           0x05
#define QC_ERR_FINAL_SIZE_ERROR             0x06
#define QC_ERR_FRAME_ENCODING_ERROR         0x07
#define QC_ERR_TRANSPORT_PARAMETER_ERROR    0x08
#define QC_ERR_CONNECTION_ID_LIMIT_ERROR    0x09
#define QC_ERR_PROTOCOL_VIOLATION           0x0a
#define QC_ERR_INVALID_TOKEN                0x0b
#define QC_ERR_APPLICATION_ERROR            0x0c
#define QC_ERR_CRYPTO_BUFFER_EXCEEDED       0x0d
#define QC_ERR_KEY_UPDATE_ERROR             0x0e
#define QC_ERR_AEAD_LIMIT_REACHED           0x0f
#define QC_ERR_NO_VIABLE_PATH               0x10
/* 256 TLS reserved errors 0x100-0x1ff. */
#define QC_ERR_CRYPTO_ERROR                0x100

/* The maximum number of QUIC packets stored by the fd I/O handler by QUIC
 * connection. Must be a power of two.
 */
#define QUIC_CONN_MAX_PACKET  64

#define QUIC_STATELESS_RESET_TOKEN_LEN 16

#define           QUIC_EV_CONN_NEW       (1ULL << 0)
#define           QUIC_EV_CONN_INIT      (1ULL << 1)
#define           QUIC_EV_CONN_ISEC      (1ULL << 2)
#define           QUIC_EV_CONN_RSEC      (1ULL << 3)
#define           QUIC_EV_CONN_WSEC      (1ULL << 4)
#define           QUIC_EV_CONN_RWSEC     (1ULL << 5)
#define           QUIC_EV_CONN_LPKT      (1ULL << 6)
#define           QUIC_EV_CONN_SPKT      (1ULL << 7)
#define           QUIC_EV_CONN_ENCPKT    (1ULL << 8)
#define           QUIC_EV_CONN_HPKT      (1ULL << 9)
#define           QUIC_EV_CONN_PAPKT     (1ULL << 10)
#define           QUIC_EV_CONN_PAPKTS    (1ULL << 11)
#define           QUIC_EV_CONN_HDSHK     (1ULL << 12)
#define           QUIC_EV_CONN_RMHP      (1ULL << 13)
#define           QUIC_EV_CONN_PRSHPKT   (1ULL << 14)
#define           QUIC_EV_CONN_PRSAPKT   (1ULL << 15)
#define           QUIC_EV_CONN_PRSFRM    (1ULL << 16)
#define           QUIC_EV_CONN_PRSAFRM   (1ULL << 17)
#define           QUIC_EV_CONN_BFRM      (1ULL << 18)
#define           QUIC_EV_CONN_PHPKTS    (1ULL << 19)
#define           QUIC_EV_CONN_TRMHP     (1ULL << 20)
#define           QUIC_EV_CONN_ELRMHP    (1ULL << 21)
#define           QUIC_EV_CONN_ELRXPKTS  (1ULL << 22)
#define           QUIC_EV_CONN_SSLDATA   (1ULL << 23)
#define           QUIC_EV_CONN_RXCDATA   (1ULL << 24)
#define           QUIC_EV_CONN_ADDDATA   (1ULL << 25)
#define           QUIC_EV_CONN_FFLIGHT   (1ULL << 26)
#define           QUIC_EV_CONN_SSLALERT  (1ULL << 27)
#define           QUIC_EV_CONN_PSTRM     (1ULL << 28)
#define           QUIC_EV_CONN_RTTUPDT   (1ULL << 29)
#define           QUIC_EV_CONN_CC        (1ULL << 30)
#define           QUIC_EV_CONN_SPPKTS    (1ULL << 31)
#define           QUIC_EV_CONN_PKTLOSS   (1ULL << 32)
#define           QUIC_EV_CONN_STIMER    (1ULL << 33)
#define           QUIC_EV_CONN_PTIMER    (1ULL << 34)
#define           QUIC_EV_CONN_SPTO      (1ULL << 35)
#define           QUIC_EV_CONN_BCFRMS    (1ULL << 36)
#define           QUIC_EV_CONN_XPRTSEND  (1ULL << 37)
#define           QUIC_EV_CONN_XPRTRECV  (1ULL << 38)

/* Similar to kernel min()/max() definitions. */
#define QUIC_MIN(a, b) ({ \
    typeof(a) _a = (a);   \
    typeof(b) _b = (b);   \
    (void) (&_a == &_b);  \
    _a < _b ? _a : _b; })

#define QUIC_MAX(a, b) ({ \
    typeof(a) _a = (a);   \
    typeof(b) _b = (b);   \
    (void) (&_a == &_b);  \
    _a > _b ? _a : _b; })

/* Size of the internal buffer of QUIC TX ring buffers (must be a power of 2) */
#define QUIC_TX_RING_BUFSZ  (1UL << 12)
/* Size of the internal buffer of QUIC RX buffer. */
#define QUIC_RX_BUFSZ  (1UL << 18)
/* Size of the QUIC RX buffer for the connections */
#define QUIC_CONN_RX_BUFSZ (1UL << 14)

extern struct trace_source trace_quic;
extern struct pool_head *pool_head_quic_tx_ring;
extern struct pool_head *pool_head_quic_rxbuf;
extern struct pool_head *pool_head_quic_rx_packet;
extern struct pool_head *pool_head_quic_tx_packet;
extern struct pool_head *pool_head_quic_frame;

/* QUIC connection id data.
 *
 * This struct is used by ebmb_node structs as last member of flexible arrays.
 * So do not change the order of the member of quic_cid struct.
 * <data> member must be the first one.
 */
struct quic_cid {
	unsigned char data[QUIC_CID_MAXLEN + sizeof(in_port_t) + sizeof(struct in6_addr)];
	unsigned char len; /* size of QUIC CID, excluding possible concatenated address */
	unsigned char addrlen; /* size of port + IP if present in data*/
};

/* QUIC connection id attached to a QUIC connection.
 *
 * This structure is used to match received packets DCIDs with the
 * corresponding QUIC connection.
 */
struct quic_connection_id {
	struct eb64_node seq_num;
	uint64_t retire_prior_to;
	unsigned char stateless_reset_token[QUIC_STATELESS_RESET_TOKEN_LEN];

	struct ebmb_node node; /* node for receiver tree, cid.data as key */
	struct quic_cid cid;   /* CID data */

	struct quic_conn *qc;  /* QUIC connection using this CID */
};

struct preferred_address {
	uint16_t ipv4_port;
	uint16_t ipv6_port;
	uint8_t ipv4_addr[4];
	uint8_t ipv6_addr[16];
	struct quic_cid cid;
	uint8_t stateless_reset_token[QUIC_STATELESS_RESET_TOKEN_LEN];
};

/* Default values for the absent transport parameters */
#define QUIC_DFLT_MAX_UDP_PAYLOAD_SIZE   65527 /* bytes */
#define QUIC_DFLT_ACK_DELAY_COMPONENT        3 /* milliseconds */
#define QUIC_DFLT_MAX_ACK_DELAY             25 /* milliseconds */
#define QUIC_ACTIVE_CONNECTION_ID_LIMIT      2 /* number of connections */

/* Types of QUIC transport parameters */
#define QUIC_TP_ORIGINAL_DESTINATION_CONNECTION_ID   0
#define QUIC_TP_MAX_IDLE_TIMEOUT                     1
#define QUIC_TP_STATELESS_RESET_TOKEN                2
#define QUIC_TP_MAX_UDP_PAYLOAD_SIZE                 3
#define QUIC_TP_INITIAL_MAX_DATA                     4
#define QUIC_TP_INITIAL_MAX_STREAM_DATA_BIDI_LOCAL   5
#define QUIC_TP_INITIAL_MAX_STREAM_DATA_BIDI_REMOTE  6
#define QUIC_TP_INITIAL_MAX_STREAM_DATA_UNI          7
#define QUIC_TP_INITIAL_MAX_STREAMS_BIDI             8
#define QUIC_TP_INITIAL_MAX_STREAMS_UNI              9
#define QUIC_TP_ACK_DELAY_EXPONENT                  10
#define QUIC_TP_MAX_ACK_DELAY                       11
#define QUIC_TP_DISABLE_ACTIVE_MIGRATION            12
#define QUIC_TP_PREFERRED_ADDRESS                   13
#define QUIC_TP_ACTIVE_CONNECTION_ID_LIMIT          14
#define QUIC_TP_INITIAL_SOURCE_CONNECTION_ID        15

/*
 * These defines are not for transport parameter type, but the maximum accepted value for
 * transport parameter types.
 */
#define QUIC_TP_ACK_DELAY_EXPONENT_LIMIT 20
#define QUIC_TP_MAX_ACK_DELAY_LIMIT      (1UL << 14)

/* The maximum length of encoded transport parameters for any QUIC peer. */
#define QUIC_TP_MAX_ENCLEN    128
/*
 * QUIC transport parameters.
 * Note that forbidden parameters sent by clients MUST generate TRANSPORT_PARAMETER_ERROR errors.
 */
struct quic_transport_params {
	uint64_t max_idle_timeout;
	uint64_t max_udp_payload_size;                 /* Default: 65527 bytes (max of UDP payload for IPv6) */
	uint64_t initial_max_data;
	uint64_t initial_max_stream_data_bidi_local;
	uint64_t initial_max_stream_data_bidi_remote;
	uint64_t initial_max_stream_data_uni;
	uint64_t initial_max_streams_bidi;
	uint64_t initial_max_streams_uni;
	uint64_t ack_delay_exponent;                   /* Default: 3, max: 20 */
	uint64_t max_ack_delay;                        /* Default: 3ms, max: 2^14ms*/
	uint64_t active_connection_id_limit;

	/* Booleans */
	uint8_t disable_active_migration;
	uint8_t with_stateless_reset_token;
	uint8_t with_preferred_address;
	uint8_t original_destination_connection_id_present;
	uint8_t initial_source_connection_id_present;

	uint8_t stateless_reset_token[QUIC_STATELESS_RESET_TOKEN_LEN]; /* Forbidden for clients */
	/*
	 * MUST be sent by servers.
	 * When received by clients, must be set to 1 if present.
	 */
	struct quic_cid original_destination_connection_id;            /* Forbidden for clients */
	/* MUST be present both for servers and clients. */
	struct quic_cid initial_source_connection_id;
	struct preferred_address preferred_address;                    /* Forbidden for clients */
};

/* Structure to hold a range of ACKs sent in ACK frames. */
struct quic_arng {
	int64_t first;
	int64_t last;
};

/* Structure to hold a range of ACKs to be store as a node in a tree of
 * ACK ranges.
 */
struct quic_arng_node {
	struct eb64_node first;
	uint64_t last;
};

/* Structure to maintain a set of ACK ranges to be used to build ACK frames. */
struct quic_arngs {
	/* ebtree of ACK ranges organized by their first value. */
	struct eb_root root;
	/* The number of ACK ranges is this tree */
	size_t sz;
	/* The number of bytes required to encode this ACK ranges lists. */
	size_t enc_sz;
};

/* Flag the packet number space as having received an ACK frame */
#define QUIC_FL_PKTNS_ACK_RECEIVED_BIT 0
#define QUIC_FL_PKTNS_ACK_RECEIVED  (1UL << QUIC_FL_PKTNS_ACK_RECEIVED_BIT)

/* The maximum number of dgrams which may be sent upon PTO expirations. */
#define QUIC_MAX_NB_PTO_DGRAMS         2

/* QUIC packet number space */
struct quic_pktns {
	struct {
		/* List of frames to send. */
		struct mt_list frms;
		/* Next packet number to use for transmissions. */
		int64_t next_pn;
		/* Largest acked sent packet. */
		int64_t largest_acked_pn;
		/* The packet which has been sent. */
		struct eb_root pkts;
		/* The time the most recent ack-eliciting packer was sent. */
		unsigned int time_of_last_eliciting;
		/* The time this packet number space has experienced packet loss. */
		unsigned int loss_time;
		/* Boolean to denote if we must send probe packet. */
		unsigned int pto_probe;
		/* In flight bytes for this packet number space. */
		size_t in_flight;
	} tx;
	struct {
		/* Largest packet number */
		int64_t largest_pn;
		struct quic_arngs arngs;
	} rx;
	unsigned int flags;
};

/* The QUIC packet numbers are 62-bits integers */
#define QUIC_MAX_PACKET_NUM      ((1ULL << 62) - 1)

/* Default QUIC connection transport parameters */
extern struct quic_transport_params quic_dflt_transport_params;

/* Flag a received packet as being an ack-eliciting packet. */
#define QUIC_FL_RX_PACKET_ACK_ELICITING (1UL << 0)

struct quic_rx_packet {
	struct mt_list list;
	struct mt_list rx_list;
	struct list qc_rx_pkt_list;
	struct quic_conn *qc;
	unsigned char type;
	uint32_t version;
	/* Initial desctination connection ID. */
	struct quic_cid dcid;
	struct quic_cid scid;
	size_t pn_offset;
	/* Packet number */
	int64_t pn;
	/* Packet number length */
	uint32_t pnl;
	uint64_t token_len;
	/* Packet length */
	uint64_t len;
	/* Packet length before decryption */
	uint64_t raw_len;
	/* Additional authenticated data length */
	size_t aad_len;
	unsigned char *data;
	struct eb64_node pn_node;
	volatile unsigned int refcnt;
	/* Source address of this packet. */
	struct sockaddr_storage saddr;
	unsigned int flags;
};

/* UDP datagram context used by the I/O handler receiver callbacks.
 * Useful to store the connection
 */
struct quic_dgram_ctx {
	struct quic_conn *qc;
	struct quic_cid dcid;
	void *owner;
};

/* QUIC packet reader. */
typedef ssize_t qpkt_read_func(unsigned char *buf,
                               const unsigned char *end,
                               struct quic_rx_packet *qpkt,
                               struct quic_dgram_ctx *dgram_ctx,
                               struct sockaddr_storage *saddr);

/* Structure to store enough information about the RX CRYPTO frames. */
struct quic_rx_crypto_frm {
	struct eb64_node offset_node;
	uint64_t len;
	const unsigned char *data;
	struct quic_rx_packet *pkt;
};

/* Structure to store information about RX STREAM frames. */
struct quic_rx_strm_frm {
	struct eb64_node offset_node;
	uint64_t len;
	const unsigned char *data;
	struct quic_rx_packet *pkt;
};

/* Flag a sent packet as being an ack-eliciting packet. */
#define QUIC_FL_TX_PACKET_ACK_ELICITING (1UL << 0)
/* Flag a sent packet as containing a PADDING frame. */
#define QUIC_FL_TX_PACKET_PADDING       (1UL << 1)
/* Flag a sent packet as being in flight. */
#define QUIC_FL_TX_PACKET_IN_FLIGHT     (QUIC_FL_TX_PACKET_ACK_ELICITING | QUIC_FL_TX_PACKET_PADDING)

/* Structure to store enough information about TX QUIC packets. */
struct quic_tx_packet {
	/* List entry point. */
	struct list list;
	/* Packet length */
	size_t len;
	/* This is not the packet length but the length of outstanding data
	 * for in flight TX packet.
	 */
	size_t in_flight_len;
	struct eb64_node pn_node;
	/* The list of frames of this packet. */
	struct list frms;
	/* The time this packet was sent (usec). */
	unsigned int time_sent;
	/* Packet number spakce. */
	struct quic_pktns *pktns;
	/* Flags. */
	unsigned int flags;
	/* Reference counter */
	int refcnt;
	/* Next packet in the same datagram */
	struct quic_tx_packet *next;
	unsigned char type;
};

#define QUIC_CRYPTO_BUF_SHIFT  10
#define QUIC_CRYPTO_BUF_MASK   ((1UL << QUIC_CRYPTO_BUF_SHIFT) - 1)
/* The maximum allowed size of CRYPTO data buffer provided by the TLS stack. */
#define QUIC_CRYPTO_BUF_SZ    (1UL << QUIC_CRYPTO_BUF_SHIFT) /* 1 KB */

/* The maximum number of bytes of CRYPTO data in flight during handshakes. */
#define QUIC_CRYPTO_IN_FLIGHT_MAX 4096

/*
 * CRYPTO buffer struct.
 * Such buffers are used to send CRYPTO data.
 */
struct quic_crypto_buf {
	unsigned char data[QUIC_CRYPTO_BUF_SZ];
	size_t sz;
};

/* QUIC buffer structure used to build outgoing packets. */
struct q_buf {
	/* Points to the data in this buffer. */
	unsigned char *area;
	/* Points to the current position to write into this buffer. */
	unsigned char *pos;
	/* Point to the end of this buffer past one. */
	const unsigned char *end;
	/* The number of data bytes in this buffer. */
	size_t data;
	/* The list of packets attached to this buffer which have not been already sent. */
	struct list pkts;
};

struct quic_enc_level {
	enum ssl_encryption_level_t level;
	struct quic_tls_ctx tls_ctx;
	struct {
		/* The packets received by the listener I/O handler
		   with header protection removed. */
		struct eb_root pkts;
		/* <pkts> root must be protected from concurrent accesses */
		__decl_thread(HA_RWLOCK_T pkts_rwlock);
		/* Liste of QUIC packets with protected header. */
		struct mt_list pqpkts;
		/* Crypto frames */
		struct {
			uint64_t offset;
			struct eb_root frms;
		} crypto;
	} rx;
	struct {
		struct {
			struct quic_crypto_buf **bufs;
			/* The number of element in use in the previous array. */
			size_t nb_buf;
			/* The total size of the CRYPTO data stored in the CRYPTO buffers. */
			size_t sz;
			/* The offset of the CRYPT0 data stream. */
			uint64_t offset;
		} crypto;
	} tx;
	struct quic_pktns *pktns;
};

struct quic_path {
	/* Control congestion. */
	struct quic_cc cc;
	/* Packet loss detection information. */
	struct quic_loss loss;

	/* MTU. */
	size_t mtu;
	/* Congestion window. */
	uint64_t cwnd;
	/* Minimum congestion window. */
	uint64_t min_cwnd;
	/* Prepared data to be sent (in bytes). */
	uint64_t prep_in_flight;
	/* Outstanding data (in bytes). */
	uint64_t in_flight;
	/* Number of in flight ack-eliciting packets. */
	uint64_t ifae_pkts;
};

/* QUIC ring buffer */
struct qring {
	struct cbuf *cbuf;
	struct mt_list mt_list;
};

/* QUIC RX buffer */
struct rxbuf {
	struct buffer buf;
	struct mt_list mt_list;
};

/* The number of buffers for outgoing packets (must be a power of two). */
#define QUIC_CONN_TX_BUFS_NB 8
#define QUIC_CONN_TX_BUF_SZ  QUIC_PACKET_MAXLEN

/* Flag the packet number space as requiring an ACK frame to be sent. */
#define QUIC_FL_PKTNS_ACK_REQUIRED_BIT 0
#define QUIC_FL_PKTNS_ACK_REQUIRED  (1UL << QUIC_FL_PKTNS_ACK_REQUIRED_BIT)

/* Flags at connection level */
#define QUIC_FL_CONN_ANTI_AMPLIFICATION_REACHED (1U << 0)
#define QUIC_FL_CONN_IMMEDIATE_CLOSE            (1U << 31)
struct quic_conn {
	uint32_t version;
	/* QUIC transport parameters TLS extension */
	int tps_tls_ext;
	/* Thread ID this connection is attached to */
	int tid;
	int state;
	uint64_t err_code;
	unsigned char enc_params[QUIC_TP_MAX_ENCLEN]; /* encoded QUIC transport parameters */
	size_t enc_params_len;

	/*
	 * Original DCID used by clients on first Initial packets.
	 * <odcid> is concatenated with the socket src address.
	 */
	struct ebmb_node odcid_node;
	struct quic_cid odcid;

	struct quic_cid dcid; /* DCID of our endpoint - not updated whan a new DCID is used */
	struct ebmb_node scid_node; /* used only for client side (backend) */
	struct quic_cid scid; /* first SCID of our endpoint - not updated when a new SCID is used */
	struct eb_root cids; /* tree of quic_connection_id - used to match a received packet DCID with a connection */

	struct quic_enc_level els[QUIC_TLS_ENC_LEVEL_MAX];
	struct quic_pktns pktns[QUIC_TLS_PKTNS_MAX];

	struct ssl_sock_ctx *xprt_ctx;
	/* Used only to reach the tasklet for the I/O handler from this quic_conn object. */
	struct connection *conn;
	/* Output buffer used during the handshakes. */
	struct {
		unsigned char data[QUIC_PACKET_MAXLEN];
		unsigned char *pos;
	} obuf;

	struct {
		/* The remaining frames to send. */
		struct list frms_to_send;

		/* The size of the previous array. */
		size_t nb_buf;
		/* Writer index. */
		int wbuf;
		/* Reader index. */
		int rbuf;
		/* Number of sent bytes. */
		uint64_t bytes;
		/* Number of bytes for prepared packets */
		uint64_t prep_bytes;
		/* The number of datagrams which may be sent
		 * when sending probe packets.
		 */
		int nb_pto_dgrams;
		/* Transport parameters sent by the peer */
		struct quic_transport_params params;
		/* A pointer to a list of TX ring buffers */
		struct mt_list *qring_list;
	} tx;
	struct {
		/* Number of received bytes. */
		uint64_t bytes;
		/* Number of ack-eliciting received packets. */
		size_t nb_ack_eliciting;
		/* Transport parameters the peer will receive */
		struct quic_transport_params params;
		/* RX buffer */
		struct buffer buf;
		/* RX buffer read/write lock */
		__decl_thread(HA_RWLOCK_T buf_rwlock);
		struct list pkt_list;
	} rx;
	struct {
		struct quic_tls_kp prv_rx;
		struct quic_tls_kp nxt_rx;
		struct quic_tls_kp nxt_tx;
	} ku;
	unsigned int max_ack_delay;
	struct quic_path paths[1];
	struct quic_path *path;

	struct listener *li; /* only valid for frontend connections */
	/* MUX */
	struct qcc *qcc;
	struct task *timer_task;
	unsigned int timer;
	unsigned int flags;
};

#endif /* USE_QUIC */
#endif /* _HAPROXY_XPRT_QUIC_T_H */