msquic.h

/*++

    Copyright (c) Microsoft Corporation.
    Licensed under the MIT License.

Abstract:

    Declarations for the MsQuic API, which enables applications and drivers to
    create QUIC connections as a client or server.

    For more detailed information, see ../docs/API.md

Supported Platforms:

    Windows User mode
    Windows Kernel mode
    Linux User mode

--*/

#ifndef _MSQUIC_
#define _MSQUIC_

#ifdef _WIN32
#pragma once

#pragma warning(disable:4201)  // nonstandard extension used: nameless struct/union
#pragma warning(disable:4214)  // nonstandard extension used: bit field types other than int
#endif

#ifdef _KERNEL_MODE
#include "msquic_winkernel.h"
#elif _WIN32
#include "msquic_winuser.h"
#elif __linux__ || __APPLE__ || __FreeBSD__
#include "msquic_posix.h"
#else
#error "Unsupported Platform"
#endif

#if defined(__cplusplus)
extern "C" {
#endif

typedef struct QUIC_HANDLE *HQUIC;

//
// The maximum value that can be encoded in a 62-bit integer.
//
#define QUIC_UINT62_MAX ((1ULL << 62U) - 1)

//
// Represents a 62-bit integer.
//
typedef _In_range_(0, QUIC_UINT62_MAX) uint64_t QUIC_UINT62;

//
// An ALPN must not exceed 255 bytes, and must not be zero-length.
//
#define QUIC_MAX_ALPN_LENGTH            255

//
// A server name must not exceed 65535 bytes.
//
#define QUIC_MAX_SNI_LENGTH             65535

//
// The maximum number of bytes of application data a server application can
// send in a resumption ticket.
//
#define QUIC_MAX_RESUMPTION_APP_DATA_LENGTH     1000

//
// The number of bytes of stateless reset key.
//
#define QUIC_STATELESS_RESET_KEY_LENGTH       32

typedef enum QUIC_TLS_PROVIDER {
    QUIC_TLS_PROVIDER_SCHANNEL                  = 0x0000,
    QUIC_TLS_PROVIDER_OPENSSL                   = 0x0001,
} QUIC_TLS_PROVIDER;

typedef enum QUIC_EXECUTION_PROFILE {
    QUIC_EXECUTION_PROFILE_LOW_LATENCY,         // Default
    QUIC_EXECUTION_PROFILE_TYPE_MAX_THROUGHPUT,
    QUIC_EXECUTION_PROFILE_TYPE_SCAVENGER,
    QUIC_EXECUTION_PROFILE_TYPE_REAL_TIME,
} QUIC_EXECUTION_PROFILE;

typedef enum QUIC_LOAD_BALANCING_MODE {
    QUIC_LOAD_BALANCING_DISABLED,               // Default
    QUIC_LOAD_BALANCING_SERVER_ID_IP,           // Encodes IP address in Server ID
    QUIC_LOAD_BALANCING_SERVER_ID_FIXED,        // Encodes a fixed 4-byte value in Server ID
    QUIC_LOAD_BALANCING_COUNT,                  // The number of supported load balancing modes
                                                // MUST BE LAST
} QUIC_LOAD_BALANCING_MODE;

typedef enum QUIC_TLS_ALERT_CODES {
    QUIC_TLS_ALERT_CODE_SUCCESS = 0xFFFF,       // Not a real TlsAlert
    QUIC_TLS_ALERT_CODE_UNEXPECTED_MESSAGE = 10,
    QUIC_TLS_ALERT_CODE_BAD_CERTIFICATE = 42,
    QUIC_TLS_ALERT_CODE_UNSUPPORTED_CERTIFICATE = 43,
    QUIC_TLS_ALERT_CODE_CERTIFICATE_REVOKED = 44,
    QUIC_TLS_ALERT_CODE_CERTIFICATE_EXPIRED = 45,
    QUIC_TLS_ALERT_CODE_CERTIFICATE_UNKNOWN = 46,
    QUIC_TLS_ALERT_CODE_ILLEGAL_PARAMETER = 47,
    QUIC_TLS_ALERT_CODE_UNKNOWN_CA = 48,
    QUIC_TLS_ALERT_CODE_ACCESS_DENIED = 49,
    QUIC_TLS_ALERT_CODE_INSUFFICIENT_SECURITY = 71,
    QUIC_TLS_ALERT_CODE_INTERNAL_ERROR = 80,
    QUIC_TLS_ALERT_CODE_USER_CANCELED = 90,
    QUIC_TLS_ALERT_CODE_CERTIFICATE_REQUIRED = 116,
    QUIC_TLS_ALERT_CODE_MAX = 255,
} QUIC_TLS_ALERT_CODES;

typedef enum QUIC_CREDENTIAL_TYPE {
    QUIC_CREDENTIAL_TYPE_NONE,
    QUIC_CREDENTIAL_TYPE_CERTIFICATE_HASH,
    QUIC_CREDENTIAL_TYPE_CERTIFICATE_HASH_STORE,
    QUIC_CREDENTIAL_TYPE_CERTIFICATE_CONTEXT,
    QUIC_CREDENTIAL_TYPE_CERTIFICATE_FILE,
    QUIC_CREDENTIAL_TYPE_CERTIFICATE_FILE_PROTECTED,
    QUIC_CREDENTIAL_TYPE_CERTIFICATE_PKCS12,
} QUIC_CREDENTIAL_TYPE;

typedef enum QUIC_CREDENTIAL_FLAGS {
    QUIC_CREDENTIAL_FLAG_NONE                                   = 0x00000000,
    QUIC_CREDENTIAL_FLAG_CLIENT                                 = 0x00000001, // Lack of client flag indicates server.
    QUIC_CREDENTIAL_FLAG_LOAD_ASYNCHRONOUS                      = 0x00000002,
    QUIC_CREDENTIAL_FLAG_NO_CERTIFICATE_VALIDATION              = 0x00000004,
    QUIC_CREDENTIAL_FLAG_ENABLE_OCSP                            = 0x00000008, // Schannel only currently
    QUIC_CREDENTIAL_FLAG_INDICATE_CERTIFICATE_RECEIVED          = 0x00000010,
    QUIC_CREDENTIAL_FLAG_DEFER_CERTIFICATE_VALIDATION           = 0x00000020,
    QUIC_CREDENTIAL_FLAG_REQUIRE_CLIENT_AUTHENTICATION          = 0x00000040,
    QUIC_CREDENTIAL_FLAG_USE_TLS_BUILTIN_CERTIFICATE_VALIDATION = 0x00000080, // OpenSSL only currently
    QUIC_CREDENTIAL_FLAG_REVOCATION_CHECK_END_CERT              = 0x00000100, // Schannel only currently
    QUIC_CREDENTIAL_FLAG_REVOCATION_CHECK_CHAIN                 = 0x00000200, // Schannel only currently
    QUIC_CREDENTIAL_FLAG_REVOCATION_CHECK_CHAIN_EXCLUDE_ROOT    = 0x00000400, // Schannel only currently
    QUIC_CREDENTIAL_FLAG_IGNORE_NO_REVOCATION_CHECK             = 0x00000800, // Schannel only currently
    QUIC_CREDENTIAL_FLAG_IGNORE_REVOCATION_OFFLINE              = 0x00001000, // Schannel only currently
    QUIC_CREDENTIAL_FLAG_SET_ALLOWED_CIPHER_SUITES              = 0x00002000,
    QUIC_CREDENTIAL_FLAG_USE_PORTABLE_CERTIFICATES              = 0x00004000,
    QUIC_CREDENTIAL_FLAG_USE_SUPPLIED_CREDENTIALS               = 0x00008000, // Schannel only
    QUIC_CREDENTIAL_FLAG_USE_SYSTEM_MAPPER                      = 0x00010000, // Schannel only
    QUIC_CREDENTIAL_FLAG_CACHE_ONLY_URL_RETRIEVAL               = 0x00020000, // Windows only currently
    QUIC_CREDENTIAL_FLAG_REVOCATION_CHECK_CACHE_ONLY            = 0x00040000, // Windows only currently
    QUIC_CREDENTIAL_FLAG_INPROC_PEER_CERTIFICATE                = 0x00080000, // Schannel only
    QUIC_CREDENTIAL_FLAG_SET_CA_CERTIFICATE_FILE                = 0x00100000, // OpenSSL only currently
    QUIC_CREDENTIAL_FLAG_DISABLE_AIA                            = 0x00200000, // Schannel only currently
    QUIC_CREDENTIAL_FLAG_SET_CA_CERTIFICATE_BLOB                = 0x00400000, // OpenSSL only currently
} QUIC_CREDENTIAL_FLAGS;

DEFINE_ENUM_FLAG_OPERATORS(QUIC_CREDENTIAL_FLAGS)

typedef enum QUIC_ALLOWED_CIPHER_SUITE_FLAGS {
    QUIC_ALLOWED_CIPHER_SUITE_NONE                      = 0x0,
    QUIC_ALLOWED_CIPHER_SUITE_AES_128_GCM_SHA256        = 0x1,
    QUIC_ALLOWED_CIPHER_SUITE_AES_256_GCM_SHA384        = 0x2,
    QUIC_ALLOWED_CIPHER_SUITE_CHACHA20_POLY1305_SHA256  = 0x4,  // Not supported on Schannel
} QUIC_ALLOWED_CIPHER_SUITE_FLAGS;

DEFINE_ENUM_FLAG_OPERATORS(QUIC_ALLOWED_CIPHER_SUITE_FLAGS);

typedef enum QUIC_CERTIFICATE_HASH_STORE_FLAGS {
    QUIC_CERTIFICATE_HASH_STORE_FLAG_NONE           = 0x0000,
    QUIC_CERTIFICATE_HASH_STORE_FLAG_MACHINE_STORE  = 0x0001,
} QUIC_CERTIFICATE_HASH_STORE_FLAGS;

DEFINE_ENUM_FLAG_OPERATORS(QUIC_CERTIFICATE_HASH_STORE_FLAGS)

typedef enum QUIC_CONNECTION_SHUTDOWN_FLAGS {
    QUIC_CONNECTION_SHUTDOWN_FLAG_NONE      = 0x0000,
    QUIC_CONNECTION_SHUTDOWN_FLAG_SILENT    = 0x0001,   // Don't send the close frame over the network.
} QUIC_CONNECTION_SHUTDOWN_FLAGS;

DEFINE_ENUM_FLAG_OPERATORS(QUIC_CONNECTION_SHUTDOWN_FLAGS)

typedef enum QUIC_SERVER_RESUMPTION_LEVEL {
    QUIC_SERVER_NO_RESUME,
    QUIC_SERVER_RESUME_ONLY,
    QUIC_SERVER_RESUME_AND_ZERORTT,
} QUIC_SERVER_RESUMPTION_LEVEL;

typedef enum QUIC_SEND_RESUMPTION_FLAGS {
    QUIC_SEND_RESUMPTION_FLAG_NONE          = 0x0000,
    QUIC_SEND_RESUMPTION_FLAG_FINAL         = 0x0001,   // Free TLS state after sending this ticket.
} QUIC_SEND_RESUMPTION_FLAGS;

DEFINE_ENUM_FLAG_OPERATORS(QUIC_SEND_RESUMPTION_FLAGS)

typedef enum QUIC_STREAM_SCHEDULING_SCHEME {
    QUIC_STREAM_SCHEDULING_SCHEME_FIFO          = 0x0000,   // Sends stream data first come, first served. (Default)
    QUIC_STREAM_SCHEDULING_SCHEME_ROUND_ROBIN   = 0x0001,   // Sends stream data evenly multiplexed.
    QUIC_STREAM_SCHEDULING_SCHEME_COUNT,                    // The number of stream scheduling schemes.
} QUIC_STREAM_SCHEDULING_SCHEME;

typedef enum QUIC_STREAM_OPEN_FLAGS {
    QUIC_STREAM_OPEN_FLAG_NONE              = 0x0000,
    QUIC_STREAM_OPEN_FLAG_UNIDIRECTIONAL    = 0x0001,   // Indicates the stream is unidirectional.
    QUIC_STREAM_OPEN_FLAG_0_RTT             = 0x0002,   // The stream was opened via a 0-RTT packet.
    QUIC_STREAM_OPEN_FLAG_DELAY_ID_FC_UPDATES = 0x0004, // Indicates stream ID flow control limit updates for the
                                                        // connection should be delayed to StreamClose.
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
    QUIC_STREAM_OPEN_FLAG_APP_OWNED_BUFFERS = 0x0008,   // No buffer will be allocated for the stream, the app must
                                                        // provide buffers (see StreamProvideReceiveBuffers)
#endif
} QUIC_STREAM_OPEN_FLAGS;

DEFINE_ENUM_FLAG_OPERATORS(QUIC_STREAM_OPEN_FLAGS)

typedef enum QUIC_STREAM_START_FLAGS {
    QUIC_STREAM_START_FLAG_NONE                 = 0x0000,
    QUIC_STREAM_START_FLAG_IMMEDIATE            = 0x0001,   // Immediately informs peer that stream is open.
    QUIC_STREAM_START_FLAG_FAIL_BLOCKED         = 0x0002,   // Only opens the stream if flow control allows.
    QUIC_STREAM_START_FLAG_SHUTDOWN_ON_FAIL     = 0x0004,   // Shutdown the stream immediately after start failure.
    QUIC_STREAM_START_FLAG_INDICATE_PEER_ACCEPT = 0x0008,   // Indicate PEER_ACCEPTED event if not accepted at start.
    QUIC_STREAM_START_FLAG_PRIORITY_WORK        = 0x0010,   // Higher priority than other connection work.
} QUIC_STREAM_START_FLAGS;

DEFINE_ENUM_FLAG_OPERATORS(QUIC_STREAM_START_FLAGS)

typedef enum QUIC_STREAM_SHUTDOWN_FLAGS {
    QUIC_STREAM_SHUTDOWN_FLAG_NONE          = 0x0000,
    QUIC_STREAM_SHUTDOWN_FLAG_GRACEFUL      = 0x0001,   // Cleanly closes the send path.
    QUIC_STREAM_SHUTDOWN_FLAG_ABORT_SEND    = 0x0002,   // Abruptly closes the send path.
    QUIC_STREAM_SHUTDOWN_FLAG_ABORT_RECEIVE = 0x0004,   // Abruptly closes the receive path.
    QUIC_STREAM_SHUTDOWN_FLAG_ABORT         = 0x0006,   // Abruptly closes both send and receive paths.
    QUIC_STREAM_SHUTDOWN_FLAG_IMMEDIATE     = 0x0008,   // Immediately sends completion events to app.
    QUIC_STREAM_SHUTDOWN_FLAG_INLINE        = 0x0010,   // Process the shutdown immediately inline. Only for calls on callbacks.
                                                        // WARNING: Can cause reentrant callbacks!
} QUIC_STREAM_SHUTDOWN_FLAGS;

DEFINE_ENUM_FLAG_OPERATORS(QUIC_STREAM_SHUTDOWN_FLAGS)

typedef enum QUIC_RECEIVE_FLAGS {
    QUIC_RECEIVE_FLAG_NONE                  = 0x0000,
    QUIC_RECEIVE_FLAG_0_RTT                 = 0x0001,   // Data was encrypted with 0-RTT key.
    QUIC_RECEIVE_FLAG_FIN                   = 0x0002,   // FIN was included with this data.
} QUIC_RECEIVE_FLAGS;

DEFINE_ENUM_FLAG_OPERATORS(QUIC_RECEIVE_FLAGS)

typedef enum QUIC_SEND_FLAGS {
    QUIC_SEND_FLAG_NONE                     = 0x0000,
    QUIC_SEND_FLAG_ALLOW_0_RTT              = 0x0001,   // Allows the use of encrypting with 0-RTT key.
    QUIC_SEND_FLAG_START                    = 0x0002,   // Asynchronously starts the stream with the sent data.
    QUIC_SEND_FLAG_FIN                      = 0x0004,   // Indicates the request is the one last sent on the stream.
    QUIC_SEND_FLAG_DGRAM_PRIORITY           = 0x0008,   // Indicates the datagram is higher priority than others.
    QUIC_SEND_FLAG_DELAY_SEND               = 0x0010,   // Indicates the send should be delayed because more will be queued soon.
    QUIC_SEND_FLAG_CANCEL_ON_LOSS           = 0x0020,   // Indicates that a stream is to be cancelled when packet loss is detected.
    QUIC_SEND_FLAG_PRIORITY_WORK            = 0x0040,   // Higher priority than other connection work.
    QUIC_SEND_FLAG_CANCEL_ON_BLOCKED        = 0x0080,   // Indicates that a frame should be dropped when it can't be sent immediately.
} QUIC_SEND_FLAGS;

DEFINE_ENUM_FLAG_OPERATORS(QUIC_SEND_FLAGS)

typedef enum QUIC_DATAGRAM_SEND_STATE {
    QUIC_DATAGRAM_SEND_UNKNOWN,                         // Not yet sent.
    QUIC_DATAGRAM_SEND_SENT,                            // Sent and awaiting acknowledgment
    QUIC_DATAGRAM_SEND_LOST_SUSPECT,                    // Suspected as lost, but still tracked
    QUIC_DATAGRAM_SEND_LOST_DISCARDED,                  // Lost and not longer being tracked
    QUIC_DATAGRAM_SEND_ACKNOWLEDGED,                    // Acknowledged
    QUIC_DATAGRAM_SEND_ACKNOWLEDGED_SPURIOUS,           // Acknowledged after being suspected lost
    QUIC_DATAGRAM_SEND_CANCELED,                        // Canceled before send
} QUIC_DATAGRAM_SEND_STATE;

//
// Helper to determine if a datagrams state is final, and no longer tracked
// by MsQuic.
//
#define QUIC_DATAGRAM_SEND_STATE_IS_FINAL(State) \
    ((State) >= QUIC_DATAGRAM_SEND_LOST_DISCARDED)

#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES

typedef enum QUIC_GLOBAL_EXECUTION_CONFIG_FLAGS {
    QUIC_GLOBAL_EXECUTION_CONFIG_FLAG_NONE             = 0x0000,
    QUIC_GLOBAL_EXECUTION_CONFIG_FLAG_NO_IDEAL_PROC    = 0x0008,
    QUIC_GLOBAL_EXECUTION_CONFIG_FLAG_HIGH_PRIORITY    = 0x0010,
    QUIC_GLOBAL_EXECUTION_CONFIG_FLAG_AFFINITIZE       = 0x0020,
} QUIC_GLOBAL_EXECUTION_CONFIG_FLAGS;

DEFINE_ENUM_FLAG_OPERATORS(QUIC_GLOBAL_EXECUTION_CONFIG_FLAGS)

//
// A custom configuration for thread execution in QUIC.
//
typedef struct QUIC_GLOBAL_EXECUTION_CONFIG {

    QUIC_GLOBAL_EXECUTION_CONFIG_FLAGS Flags;
    uint32_t PollingIdleTimeoutUs;      // Time before a polling thread, with no work to do, sleeps.
    uint32_t ProcessorCount;
    _Field_size_(ProcessorCount)
    uint16_t ProcessorList[1];          // List of processors to use for threads.

} QUIC_GLOBAL_EXECUTION_CONFIG;

#define QUIC_GLOBAL_EXECUTION_CONFIG_MIN_SIZE \
    (uint32_t)FIELD_OFFSET(QUIC_GLOBAL_EXECUTION_CONFIG, ProcessorList)

#ifndef _KERNEL_MODE

//
// Execution Context abstraction, which allows the application layer to
// completely control execution of all MsQuic work.
//

typedef struct QUIC_EXECUTION_CONFIG {
    uint32_t IdealProcessor;
    QUIC_EVENTQ* EventQ;
} QUIC_EXECUTION_CONFIG;

typedef struct QUIC_EXECUTION QUIC_EXECUTION;

//
// This is called to create the execution contexts.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_EXECUTION_CREATE_FN)(
    _In_ QUIC_GLOBAL_EXECUTION_CONFIG_FLAGS Flags, // Used for datapath type
    _In_ uint32_t PollingIdleTimeoutUs,
    _In_ uint32_t Count,
    _In_reads_(Count) QUIC_EXECUTION_CONFIG* Configs,
    _Out_writes_(Count) QUIC_EXECUTION** Executions
    );

//
// This is called to delete the execution contexts.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
void
(QUIC_API * QUIC_EXECUTION_DELETE_FN)(
    _In_ uint32_t Count,
    _In_reads_(Count) QUIC_EXECUTION** Executions
    );

//
// This is called to allow MsQuic to process any polling work. It returns the
// number of milliseconds until the next scheduled timer expiration.
//
// TODO: Should it return an indication for if we should yield?
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
uint32_t
(QUIC_API * QUIC_EXECUTION_POLL_FN)(
    _In_ QUIC_EXECUTION* Execution
    );

#endif // _KERNEL_MODE

#endif // QUIC_API_ENABLE_PREVIEW_FEATURES

typedef struct QUIC_REGISTRATION_CONFIG { // All fields may be NULL/zero.
    const char* AppName;
    QUIC_EXECUTION_PROFILE ExecutionProfile;
} QUIC_REGISTRATION_CONFIG;

typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
_Function_class_(QUIC_CREDENTIAL_LOAD_COMPLETE)
void
(QUIC_API QUIC_CREDENTIAL_LOAD_COMPLETE)(
    _In_ HQUIC Configuration,
    _In_opt_ void* Context,
    _In_ QUIC_STATUS Status
    );

typedef QUIC_CREDENTIAL_LOAD_COMPLETE *QUIC_CREDENTIAL_LOAD_COMPLETE_HANDLER;

typedef struct QUIC_CERTIFICATE_HASH {
    uint8_t ShaHash[20];
} QUIC_CERTIFICATE_HASH;

typedef struct QUIC_CERTIFICATE_HASH_STORE {
    QUIC_CERTIFICATE_HASH_STORE_FLAGS Flags;
    uint8_t ShaHash[20];
    char StoreName[128];
} QUIC_CERTIFICATE_HASH_STORE;

typedef struct QUIC_CERTIFICATE_FILE {
    const char *PrivateKeyFile;
    const char *CertificateFile;
} QUIC_CERTIFICATE_FILE;

typedef struct QUIC_CERTIFICATE_FILE_PROTECTED {
    const char *PrivateKeyFile;
    const char *CertificateFile;
    const char *PrivateKeyPassword;
} QUIC_CERTIFICATE_FILE_PROTECTED;

typedef struct QUIC_CERTIFICATE_PKCS12 {
    const uint8_t *Asn1Blob;
    uint32_t Asn1BlobLength;
    const char *PrivateKeyPassword;     // Optional: used if provided. Ignored if NULL
} QUIC_CERTIFICATE_PKCS12;

typedef void QUIC_CERTIFICATE;          // Platform specific certificate object
typedef void QUIC_CERTIFICATE_CHAIN;    // Platform specific certificate chain object

typedef struct QUIC_CREDENTIAL_CONFIG {
    QUIC_CREDENTIAL_TYPE Type;
    QUIC_CREDENTIAL_FLAGS Flags;
    union {
        QUIC_CERTIFICATE_HASH* CertificateHash;
        QUIC_CERTIFICATE_HASH_STORE* CertificateHashStore;
        QUIC_CERTIFICATE* CertificateContext;
        QUIC_CERTIFICATE_FILE* CertificateFile;
        QUIC_CERTIFICATE_FILE_PROTECTED* CertificateFileProtected;
        QUIC_CERTIFICATE_PKCS12* CertificatePkcs12;
    };
    const char* Principal;
    void* Reserved; // Currently unused
    QUIC_CREDENTIAL_LOAD_COMPLETE_HANDLER AsyncHandler; // Optional
    QUIC_ALLOWED_CIPHER_SUITE_FLAGS AllowedCipherSuites;// Optional
    const char* CaCertificateFile;                      // Optional
    const uint8_t* CaCertificateBlob;                   // Optional
    uint32_t CaCertificateBlobLength;                   // Optional
} QUIC_CREDENTIAL_CONFIG;

//
// The maximum number of QUIC_TICKET_KEY_CONFIG that can be used at one time.
//
#define QUIC_MAX_TICKET_KEY_COUNT 16

//
// TLS New Session Ticket encryption key configuration.
//
typedef struct QUIC_TICKET_KEY_CONFIG {
    uint8_t Id[16];
    uint8_t Material[64];
    uint8_t MaterialLength;
} QUIC_TICKET_KEY_CONFIG;

//
// A single contiguous buffer.
//
typedef struct QUIC_BUFFER {
    uint32_t Length;
    _Field_size_bytes_(Length)
    uint8_t* Buffer;
} QUIC_BUFFER;

//
// All the available information describing a new incoming connection.
//
typedef struct QUIC_NEW_CONNECTION_INFO {
    uint32_t QuicVersion;
    const QUIC_ADDR* LocalAddress;
    const QUIC_ADDR* RemoteAddress;
    uint32_t CryptoBufferLength;
    uint16_t ClientAlpnListLength;
    uint16_t ServerNameLength;
    uint8_t NegotiatedAlpnLength;
    _Field_size_bytes_(CryptoBufferLength)
    const uint8_t* CryptoBuffer;
    _Field_size_bytes_(ClientAlpnListLength)
    const uint8_t* ClientAlpnList;
    _Field_size_bytes_(NegotiatedAlpnLength)
    const uint8_t* NegotiatedAlpn;
    _Field_size_bytes_opt_(ServerNameLength)
    const char* ServerName;
} QUIC_NEW_CONNECTION_INFO;

typedef enum QUIC_TLS_PROTOCOL_VERSION {
    QUIC_TLS_PROTOCOL_UNKNOWN   = 0,
    QUIC_TLS_PROTOCOL_1_3       = 0x3000,
} QUIC_TLS_PROTOCOL_VERSION;

typedef enum QUIC_CIPHER_ALGORITHM {
    QUIC_CIPHER_ALGORITHM_NONE        = 0,
    QUIC_CIPHER_ALGORITHM_AES_128     = 0x660E,
    QUIC_CIPHER_ALGORITHM_AES_256     = 0x6610,
    QUIC_CIPHER_ALGORITHM_CHACHA20    = 0x6612,     // Not supported on Schannel/BCrypt
} QUIC_CIPHER_ALGORITHM;

typedef enum QUIC_HASH_ALGORITHM {
    QUIC_HASH_ALGORITHM_NONE        = 0,
    QUIC_HASH_ALGORITHM_SHA_256     = 0x800C,
    QUIC_HASH_ALGORITHM_SHA_384     = 0x800D,
} QUIC_HASH_ALGORITHM;

typedef enum QUIC_KEY_EXCHANGE_ALGORITHM {
    QUIC_KEY_EXCHANGE_ALGORITHM_NONE  = 0,
} QUIC_KEY_EXCHANGE_ALGORITHM;

//
// See the following IANA registry for the TLS groups:
//   https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-8
//
typedef enum QUIC_TLS_GROUP {
    QUIC_TLS_GROUP_UNKNOWN              = 0,
    QUIC_TLS_GROUP_SECP256R1            = 23,
    QUIC_TLS_GROUP_SECP384R1            = 24,
    QUIC_TLS_GROUP_X25519               = 29,
    QUIC_TLS_GROUP_MLKEM512             = 512,
    QUIC_TLS_GROUP_MLKEM768             = 513,
    QUIC_TLS_GROUP_MLKEM1024            = 514,
    QUIC_TLS_GROUP_SECP256R1MLKEM768    = 4587,
    QUIC_TLS_GROUP_X25519MLKEM768       = 4588,
    QUIC_TLS_GROUP_SECP384R1MLKEM1024   = 4589,
} QUIC_TLS_GROUP;

typedef enum QUIC_CIPHER_SUITE {
    QUIC_CIPHER_SUITE_TLS_AES_128_GCM_SHA256        = 0x1301,
    QUIC_CIPHER_SUITE_TLS_AES_256_GCM_SHA384        = 0x1302,
    QUIC_CIPHER_SUITE_TLS_CHACHA20_POLY1305_SHA256  = 0x1303, // Not supported on Schannel
} QUIC_CIPHER_SUITE;

typedef enum QUIC_CONGESTION_CONTROL_ALGORITHM {
    QUIC_CONGESTION_CONTROL_ALGORITHM_CUBIC,
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
    QUIC_CONGESTION_CONTROL_ALGORITHM_BBR,
#endif
    QUIC_CONGESTION_CONTROL_ALGORITHM_MAX,
} QUIC_CONGESTION_CONTROL_ALGORITHM;

//
// All the available information describing a handshake.
//
typedef struct QUIC_HANDSHAKE_INFO {
    QUIC_TLS_PROTOCOL_VERSION TlsProtocolVersion;
    QUIC_CIPHER_ALGORITHM CipherAlgorithm;
    int32_t CipherStrength;
    QUIC_HASH_ALGORITHM Hash;
    int32_t HashStrength;
    QUIC_KEY_EXCHANGE_ALGORITHM KeyExchangeAlgorithm;
    int32_t KeyExchangeStrength;
    QUIC_CIPHER_SUITE CipherSuite;
    QUIC_TLS_GROUP TlsGroup;            // Added in v2.5
} QUIC_HANDSHAKE_INFO;

//
// All statistics available to query about a connection.
//
typedef struct QUIC_STATISTICS {
    uint64_t CorrelationId;
    uint32_t VersionNegotiation     : 1;
    uint32_t StatelessRetry         : 1;
    uint32_t ResumptionAttempted    : 1;
    uint32_t ResumptionSucceeded    : 1;
    uint32_t Rtt;                       // In microseconds
    uint32_t MinRtt;                    // In microseconds
    uint32_t MaxRtt;                    // In microseconds
    struct {
        uint64_t Start;
        uint64_t InitialFlightEnd;      // Processed all peer's Initial packets
        uint64_t HandshakeFlightEnd;    // Processed all peer's Handshake packets
    } Timing;
    struct {
        uint32_t ClientFlight1Bytes;    // Sum of TLS payloads
        uint32_t ServerFlight1Bytes;    // Sum of TLS payloads
        uint32_t ClientFlight2Bytes;    // Sum of TLS payloads
    } Handshake;
    struct {
        uint16_t PathMtu;               // Current path MTU.
        uint64_t TotalPackets;          // QUIC packets; could be coalesced into fewer UDP datagrams.
        uint64_t RetransmittablePackets;
        uint64_t SuspectedLostPackets;
        uint64_t SpuriousLostPackets;   // Actual lost is (SuspectedLostPackets - SpuriousLostPackets)
        uint64_t TotalBytes;            // Sum of UDP payloads
        uint64_t TotalStreamBytes;      // Sum of stream payloads
        uint32_t CongestionCount;       // Number of congestion events
        uint32_t PersistentCongestionCount; // Number of persistent congestion events
    } Send;
    struct {
        uint64_t TotalPackets;          // QUIC packets; could be coalesced into fewer UDP datagrams.
        uint64_t ReorderedPackets;      // Packets where packet number is less than highest seen.
        uint64_t DroppedPackets;        // Includes DuplicatePackets.
        uint64_t DuplicatePackets;
        uint64_t TotalBytes;            // Sum of UDP payloads
        uint64_t TotalStreamBytes;      // Sum of stream payloads
        uint64_t DecryptionFailures;    // Count of packet decryption failures.
        uint64_t ValidAckFrames;        // Count of receive ACK frames.
    } Recv;
    struct {
        uint32_t KeyUpdateCount;
    } Misc;
} QUIC_STATISTICS;

//
// N.B. Consumers of this struct depend on it being the same for 32-bit and
// 64-bit systems. DO NOT include any fields that have different sizes on those
// platforms, such as size_t or pointers.
//
typedef struct QUIC_STATISTICS_V2 {

    uint64_t CorrelationId;
    uint32_t VersionNegotiation     : 1;
    uint32_t StatelessRetry         : 1;
    uint32_t ResumptionAttempted    : 1;
    uint32_t ResumptionSucceeded    : 1;
    uint32_t GreaseBitNegotiated    : 1;    // Set if we negotiated the GREASE bit.
    uint32_t EcnCapable             : 1;
    uint32_t EncryptionOffloaded    : 1;    // At least one path successfully offloaded encryption
    uint32_t RESERVED               : 25;
    uint32_t Rtt;                           // In microseconds
    uint32_t MinRtt;                        // In microseconds
    uint32_t MaxRtt;                        // In microseconds

    uint64_t TimingStart;
    uint64_t TimingInitialFlightEnd;        // Processed all peer's Initial packets
    uint64_t TimingHandshakeFlightEnd;      // Processed all peer's Handshake packets

    uint32_t HandshakeClientFlight1Bytes;   // Sum of TLS payloads
    uint32_t HandshakeServerFlight1Bytes;   // Sum of TLS payloads
    uint32_t HandshakeClientFlight2Bytes;   // Sum of TLS payloads

    uint16_t SendPathMtu;                   // Current path MTU.
    uint64_t SendTotalPackets;              // QUIC packets; could be coalesced into fewer UDP datagrams.
    uint64_t SendRetransmittablePackets;
    uint64_t SendSuspectedLostPackets;
    uint64_t SendSpuriousLostPackets;       // Actual lost is (SuspectedLostPackets - SpuriousLostPackets)
    uint64_t SendTotalBytes;                // Sum of UDP payloads
    uint64_t SendTotalStreamBytes;          // Sum of stream payloads
    uint32_t SendCongestionCount;           // Number of congestion events
    uint32_t SendPersistentCongestionCount; // Number of persistent congestion events

    uint64_t RecvTotalPackets;              // QUIC packets; could be coalesced into fewer UDP datagrams.
    uint64_t RecvReorderedPackets;          // Packets where packet number is less than highest seen.
    uint64_t RecvDroppedPackets;            // Includes DuplicatePackets.
    uint64_t RecvDuplicatePackets;
    uint64_t RecvTotalBytes;                // Sum of UDP payloads
    uint64_t RecvTotalStreamBytes;          // Sum of stream payloads
    uint64_t RecvDecryptionFailures;        // Count of packet decryption failures.
    uint64_t RecvValidAckFrames;            // Count of receive ACK frames.

    uint32_t KeyUpdateCount;

    uint32_t SendCongestionWindow;          // Congestion window size

    uint32_t DestCidUpdateCount;            // Number of times the destionation CID changed.

    uint32_t SendEcnCongestionCount;        // Number of congestion events caused by ECN.

    uint8_t  HandshakeHopLimitTTL;          // The TTL value in the initial packet of the handshake.

    uint32_t RttVariance;                   // In microseconds

    // N.B. New fields must be appended to end

} QUIC_STATISTICS_V2;

typedef struct QUIC_NETWORK_STATISTICS
{
    uint32_t BytesInFlight;              // Bytes that were sent on the wire, but not yet acked
    uint64_t PostedBytes;                // Total bytes queued, but not yet acked. These may contain sent bytes that may have potentially lost too.
    uint64_t IdealBytes;                 // Ideal number of bytes required to be available to  avoid limiting throughput
    uint64_t SmoothedRTT;                // Smoothed RTT value
    uint32_t CongestionWindow;           // Congestion Window
    uint64_t Bandwidth;                  // Estimated bandwidth

} QUIC_NETWORK_STATISTICS;

#define QUIC_STRUCT_SIZE_THRU_FIELD(Struct, Field) \
    (FIELD_OFFSET(Struct, Field) + sizeof(((Struct*)0)->Field))

#define QUIC_STATISTICS_V2_SIZE_1   QUIC_STRUCT_SIZE_THRU_FIELD(QUIC_STATISTICS_V2, KeyUpdateCount)         // MsQuic v2.0 final size
#define QUIC_STATISTICS_V2_SIZE_2   QUIC_STRUCT_SIZE_THRU_FIELD(QUIC_STATISTICS_V2, DestCidUpdateCount)     // MsQuic v2.1 final size
#define QUIC_STATISTICS_V2_SIZE_3   QUIC_STRUCT_SIZE_THRU_FIELD(QUIC_STATISTICS_V2, SendEcnCongestionCount) // MsQuic v2.2 final size
#define QUIC_STATISTICS_V2_SIZE_4   QUIC_STRUCT_SIZE_THRU_FIELD(QUIC_STATISTICS_V2, RttVariance)            // MsQuic v2.5 final size

typedef struct QUIC_LISTENER_STATISTICS {

    uint64_t TotalAcceptedConnections;
    uint64_t TotalRejectedConnections;

    uint64_t BindingRecvDroppedPackets;

} QUIC_LISTENER_STATISTICS;

typedef enum QUIC_PERFORMANCE_COUNTERS {
    QUIC_PERF_COUNTER_CONN_CREATED,         // Total connections ever allocated.
    QUIC_PERF_COUNTER_CONN_HANDSHAKE_FAIL,  // Total connections that failed during handshake.
    QUIC_PERF_COUNTER_CONN_APP_REJECT,      // Total connections rejected by the application.
    QUIC_PERF_COUNTER_CONN_RESUMED,         // Total connections resumed.
    QUIC_PERF_COUNTER_CONN_ACTIVE,          // Connections currently allocated.
    QUIC_PERF_COUNTER_CONN_CONNECTED,       // Connections currently in the connected state.
    QUIC_PERF_COUNTER_CONN_PROTOCOL_ERRORS, // Total connections shutdown with a protocol error.
    QUIC_PERF_COUNTER_CONN_NO_ALPN,         // Total connection attempts with no matching ALPN.
    QUIC_PERF_COUNTER_STRM_ACTIVE,          // Current streams allocated.
    QUIC_PERF_COUNTER_PKTS_SUSPECTED_LOST,  // Total suspected packets lost
    QUIC_PERF_COUNTER_PKTS_DROPPED,         // Total packets dropped for any reason.
    QUIC_PERF_COUNTER_PKTS_DECRYPTION_FAIL, // Total packets with decryption failures.
    QUIC_PERF_COUNTER_UDP_RECV,             // Total UDP datagrams received.
    QUIC_PERF_COUNTER_UDP_SEND,             // Total UDP datagrams sent.
    QUIC_PERF_COUNTER_UDP_RECV_BYTES,       // Total UDP payload bytes received.
    QUIC_PERF_COUNTER_UDP_SEND_BYTES,       // Total UDP payload bytes sent.
    QUIC_PERF_COUNTER_UDP_RECV_EVENTS,      // Total UDP receive events.
    QUIC_PERF_COUNTER_UDP_SEND_CALLS,       // Total UDP send API calls.
    QUIC_PERF_COUNTER_APP_SEND_BYTES,       // Total bytes sent by applications.
    QUIC_PERF_COUNTER_APP_RECV_BYTES,       // Total bytes received by applications.
    QUIC_PERF_COUNTER_CONN_QUEUE_DEPTH,     // Current connections queued for processing.
    QUIC_PERF_COUNTER_CONN_OPER_QUEUE_DEPTH,// Current connection operations queued.
    QUIC_PERF_COUNTER_CONN_OPER_QUEUED,     // Total connection operations queued ever.
    QUIC_PERF_COUNTER_CONN_OPER_COMPLETED,  // Total connection operations processed ever.
    QUIC_PERF_COUNTER_WORK_OPER_QUEUE_DEPTH,// Current worker operations queued.
    QUIC_PERF_COUNTER_WORK_OPER_QUEUED,     // Total worker operations queued ever.
    QUIC_PERF_COUNTER_WORK_OPER_COMPLETED,  // Total worker operations processed ever.
    QUIC_PERF_COUNTER_PATH_VALIDATED,       // Total path challenges that succeed ever.
    QUIC_PERF_COUNTER_PATH_FAILURE,         // Total path challenges that fail ever.
    QUIC_PERF_COUNTER_SEND_STATELESS_RESET, // Total stateless reset packets sent ever.
    QUIC_PERF_COUNTER_SEND_STATELESS_RETRY, // Total stateless retry packets sent ever.
    QUIC_PERF_COUNTER_CONN_LOAD_REJECT,     // Total connections rejected due to worker load.
    QUIC_PERF_COUNTER_LISTEN_QUEUE_DEPTH,   // Current listeners queued for processing.
    QUIC_PERF_COUNTER_MAX,
} QUIC_PERFORMANCE_COUNTERS;

#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
typedef struct QUIC_VERSION_SETTINGS {

    const uint32_t* AcceptableVersions;
    const uint32_t* OfferedVersions;
    const uint32_t* FullyDeployedVersions;
    uint32_t AcceptableVersionsLength;
    uint32_t OfferedVersionsLength;
    uint32_t FullyDeployedVersionsLength;

} QUIC_VERSION_SETTINGS;
#endif

typedef struct QUIC_GLOBAL_SETTINGS {
    union {
        uint64_t IsSetFlags;
        struct {
            uint64_t RetryMemoryLimit                       : 1;
            uint64_t LoadBalancingMode                      : 1;
            uint64_t FixedServerID                          : 1;
            uint64_t RESERVED                               : 61;
        } IsSet;
    };
    uint16_t RetryMemoryLimit;
    uint16_t LoadBalancingMode;
    uint32_t FixedServerID;
} QUIC_GLOBAL_SETTINGS;

typedef struct QUIC_SETTINGS {

    union {
        uint64_t IsSetFlags;
        struct {
            uint64_t MaxBytesPerKey                         : 1;
            uint64_t HandshakeIdleTimeoutMs                 : 1;
            uint64_t IdleTimeoutMs                          : 1;
            uint64_t MtuDiscoverySearchCompleteTimeoutUs    : 1;
            uint64_t TlsClientMaxSendBuffer                 : 1;
            uint64_t TlsServerMaxSendBuffer                 : 1;
            uint64_t StreamRecvWindowDefault                : 1;
            uint64_t StreamRecvBufferDefault                : 1;
            uint64_t ConnFlowControlWindow                  : 1;
            uint64_t MaxWorkerQueueDelayUs                  : 1;
            uint64_t MaxStatelessOperations                 : 1;
            uint64_t InitialWindowPackets                   : 1;
            uint64_t SendIdleTimeoutMs                      : 1;
            uint64_t InitialRttMs                           : 1;
            uint64_t MaxAckDelayMs                          : 1;
            uint64_t DisconnectTimeoutMs                    : 1;
            uint64_t KeepAliveIntervalMs                    : 1;
            uint64_t CongestionControlAlgorithm             : 1;
            uint64_t PeerBidiStreamCount                    : 1;
            uint64_t PeerUnidiStreamCount                   : 1;
            uint64_t MaxBindingStatelessOperations          : 1;
            uint64_t StatelessOperationExpirationMs         : 1;
            uint64_t MinimumMtu                             : 1;
            uint64_t MaximumMtu                             : 1;
            uint64_t SendBufferingEnabled                   : 1;
            uint64_t PacingEnabled                          : 1;
            uint64_t MigrationEnabled                       : 1;
            uint64_t DatagramReceiveEnabled                 : 1;
            uint64_t ServerResumptionLevel                  : 1;
            uint64_t MaxOperationsPerDrain                  : 1;
            uint64_t MtuDiscoveryMissingProbeCount          : 1;
            uint64_t DestCidUpdateIdleTimeoutMs             : 1;
            uint64_t GreaseQuicBitEnabled                   : 1;
            uint64_t EcnEnabled                             : 1;
            uint64_t HyStartEnabled                         : 1;
            uint64_t StreamRecvWindowBidiLocalDefault       : 1;
            uint64_t StreamRecvWindowBidiRemoteDefault      : 1;
            uint64_t StreamRecvWindowUnidiDefault           : 1;
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
            uint64_t EncryptionOffloadAllowed               : 1;
            uint64_t ReliableResetEnabled                   : 1;
            uint64_t OneWayDelayEnabled                     : 1;
            uint64_t NetStatsEventEnabled                   : 1;
            uint64_t StreamMultiReceiveEnabled              : 1;
            uint64_t XdpEnabled                             : 1;
            uint64_t QTIPEnabled                            : 1;
            uint64_t ReservedRioEnabled                     : 1;
            uint64_t RESERVED                               : 18;
#else
            uint64_t RESERVED                               : 26;
#endif
        } IsSet;
    };

    uint64_t MaxBytesPerKey;
    uint64_t HandshakeIdleTimeoutMs;
    uint64_t IdleTimeoutMs;
    uint64_t MtuDiscoverySearchCompleteTimeoutUs;
    uint32_t TlsClientMaxSendBuffer;
    uint32_t TlsServerMaxSendBuffer;
    uint32_t StreamRecvWindowDefault;
    uint32_t StreamRecvBufferDefault;
    uint32_t ConnFlowControlWindow;
    uint32_t MaxWorkerQueueDelayUs;
    uint32_t MaxStatelessOperations;
    uint32_t InitialWindowPackets;
    uint32_t SendIdleTimeoutMs;
    uint32_t InitialRttMs;
    uint32_t MaxAckDelayMs;
    uint32_t DisconnectTimeoutMs;
    uint32_t KeepAliveIntervalMs;
    uint16_t CongestionControlAlgorithm; // QUIC_CONGESTION_CONTROL_ALGORITHM
    uint16_t PeerBidiStreamCount;
    uint16_t PeerUnidiStreamCount;
    uint16_t MaxBindingStatelessOperations;
    uint16_t StatelessOperationExpirationMs;
    uint16_t MinimumMtu;
    uint16_t MaximumMtu;
    uint8_t SendBufferingEnabled            : 1;
    uint8_t PacingEnabled                   : 1;
    uint8_t MigrationEnabled                : 1;
    uint8_t DatagramReceiveEnabled          : 1;
    uint8_t ServerResumptionLevel           : 2;    // QUIC_SERVER_RESUMPTION_LEVEL
    uint8_t GreaseQuicBitEnabled            : 1;
    uint8_t EcnEnabled                      : 1;
    uint8_t MaxOperationsPerDrain;
    uint8_t MtuDiscoveryMissingProbeCount;
    uint32_t DestCidUpdateIdleTimeoutMs;
    union {
        uint64_t Flags;
        struct {
            uint64_t HyStartEnabled            : 1;
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
            uint64_t EncryptionOffloadAllowed  : 1;
            uint64_t ReliableResetEnabled      : 1;
            uint64_t OneWayDelayEnabled        : 1;
            uint64_t NetStatsEventEnabled      : 1;
            uint64_t StreamMultiReceiveEnabled : 1;
            uint64_t XdpEnabled                : 1;
            uint64_t QTIPEnabled               : 1;
            uint64_t ReservedRioEnabled        : 1;
            uint64_t ReservedFlags             : 55;
#else
            uint64_t ReservedFlags             : 63;
#endif
        };
    };
    uint32_t StreamRecvWindowBidiLocalDefault;
    uint32_t StreamRecvWindowBidiRemoteDefault;
    uint32_t StreamRecvWindowUnidiDefault;

} QUIC_SETTINGS;

//
// This struct enables QUIC applications to support SSLKEYLOGFILE
// for debugging packet captures with e.g. Wireshark.
//

#define QUIC_TLS_SECRETS_MAX_SECRET_LEN 64
typedef struct QUIC_TLS_SECRETS {
    uint8_t SecretLength;
    struct {
        uint8_t ClientRandom : 1;
        uint8_t ClientEarlyTrafficSecret : 1;
        uint8_t ClientHandshakeTrafficSecret : 1;
        uint8_t ServerHandshakeTrafficSecret : 1;
        uint8_t ClientTrafficSecret0 : 1;
        uint8_t ServerTrafficSecret0 : 1;
    } IsSet;
    uint8_t ClientRandom[32];
    uint8_t ClientEarlyTrafficSecret[QUIC_TLS_SECRETS_MAX_SECRET_LEN];
    uint8_t ClientHandshakeTrafficSecret[QUIC_TLS_SECRETS_MAX_SECRET_LEN];
    uint8_t ServerHandshakeTrafficSecret[QUIC_TLS_SECRETS_MAX_SECRET_LEN];
    uint8_t ClientTrafficSecret0[QUIC_TLS_SECRETS_MAX_SECRET_LEN];
    uint8_t ServerTrafficSecret0[QUIC_TLS_SECRETS_MAX_SECRET_LEN];
} QUIC_TLS_SECRETS;

typedef struct QUIC_STREAM_STATISTICS {
    uint64_t ConnBlockedBySchedulingUs;
    uint64_t ConnBlockedByPacingUs;
    uint64_t ConnBlockedByAmplificationProtUs;
    uint64_t ConnBlockedByCongestionControlUs;
    uint64_t ConnBlockedByFlowControlUs;
    uint64_t StreamBlockedByIdFlowControlUs;
    uint64_t StreamBlockedByFlowControlUs;
    uint64_t StreamBlockedByAppUs;
} QUIC_STREAM_STATISTICS;

typedef enum QUIC_AEAD_ALGORITHM_TYPE {
    QUIC_AEAD_ALGORITHM_AES_128_GCM = 0,
    QUIC_AEAD_ALGORITHM_AES_256_GCM = 1,
} QUIC_AEAD_ALGORITHM_TYPE;

typedef struct QUIC_STATELESS_RETRY_CONFIG {
    QUIC_AEAD_ALGORITHM_TYPE Algorithm; // AEAD algorithm for the key.
    uint32_t RotationMs;                // Key rotation interval in milliseconds.
    uint32_t SecretLength;              // Length of the secret.
    _Field_size_bytes_(SecretLength)
        const uint8_t* Secret;          // Secret to generate the key.
} QUIC_STATELESS_RETRY_CONFIG;

//
// Functions for associating application contexts with QUIC handles. MsQuic
// provides no explicit synchronization between parallel calls to these
// functions.
//

typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
void
(QUIC_API * QUIC_SET_CONTEXT_FN)(
    _In_ _Pre_defensive_ HQUIC Handle,
    _In_opt_ void* Context
    );

typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
void*
(QUIC_API * QUIC_GET_CONTEXT_FN)(
    _In_ _Pre_defensive_ HQUIC Handle
    );

//
// Sets the event handler for the QUIC handle. The type of the handler must be
// appropriate for the type of the handle. MsQuic provides no explicit
// synchronization between parallel calls to this function or the ones above.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
void
(QUIC_API * QUIC_SET_CALLBACK_HANDLER_FN)(
    _In_ _Pre_defensive_ HQUIC Handle,
    _In_ void* Handler,
    _In_opt_ void* Context
    );

//
// Get and Set parameters on a handle.
//

#define QUIC_PARAM_PREFIX_GLOBAL                        0x01000000
#define QUIC_PARAM_PREFIX_REGISTRATION                  0x02000000
#define QUIC_PARAM_PREFIX_CONFIGURATION                 0x03000000
#define QUIC_PARAM_PREFIX_LISTENER                      0x04000000
#define QUIC_PARAM_PREFIX_CONNECTION                    0x05000000
#define QUIC_PARAM_PREFIX_TLS                           0x06000000
#define QUIC_PARAM_PREFIX_TLS_SCHANNEL                  0x07000000
#define QUIC_PARAM_PREFIX_STREAM                        0x08000000

#define QUIC_PARAM_HIGH_PRIORITY                        0x40000000 // Combine with any param to make it high priority.

#define QUIC_PARAM_IS_GLOBAL(Param) ((Param & 0x3F000000) == QUIC_PARAM_PREFIX_GLOBAL)

//
// Parameters for Global.
//
#define QUIC_PARAM_GLOBAL_RETRY_MEMORY_PERCENT          0x01000000  // uint16_t
#define QUIC_PARAM_GLOBAL_SUPPORTED_VERSIONS            0x01000001  // uint32_t[] - network byte order
#define QUIC_PARAM_GLOBAL_LOAD_BALACING_MODE            0x01000002  // uint16_t - QUIC_LOAD_BALANCING_MODE
#define QUIC_PARAM_GLOBAL_PERF_COUNTERS                 0x01000003  // uint64_t[] - Array size is QUIC_PERF_COUNTER_MAX
#define QUIC_PARAM_GLOBAL_LIBRARY_VERSION               0x01000004  // uint32_t[4]
#define QUIC_PARAM_GLOBAL_SETTINGS                      0x01000005  // QUIC_SETTINGS
#define QUIC_PARAM_GLOBAL_GLOBAL_SETTINGS               0x01000006  // QUIC_GLOBAL_SETTINGS
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
#define QUIC_PARAM_GLOBAL_VERSION_SETTINGS              0x01000007  // QUIC_VERSION_SETTINGS
#endif
#define QUIC_PARAM_GLOBAL_LIBRARY_GIT_HASH              0x01000008  // char[64]
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
#define QUIC_PARAM_GLOBAL_EXECUTION_CONFIG              0x01000009  // QUIC_GLOBAL_EXECUTION_CONFIG
#endif
#define QUIC_PARAM_GLOBAL_TLS_PROVIDER                  0x0100000A  // QUIC_TLS_PROVIDER
#define QUIC_PARAM_GLOBAL_STATELESS_RESET_KEY           0x0100000B  // uint8_t[] - Array size is QUIC_STATELESS_RESET_KEY_LENGTH
#define QUIC_PARAM_GLOBAL_STATISTICS_V2_SIZES           0x0100000C  // uint32_t[] - Array of sizes for each QUIC_STATISTICS_V2 version. Get-only. Pass a buffer of uint32_t, output count is variable. See documentation for details.
#define QUIC_PARAM_GLOBAL_STATELESS_RETRY_CONFIG        0x0100000D  // QUIC_STATELESS_RETRY_CONFIG

//
// Parameters for Registration.
//

//
// Parameters for Configuration.
//
#define QUIC_PARAM_CONFIGURATION_SETTINGS               0x03000000  // QUIC_SETTINGS
#define QUIC_PARAM_CONFIGURATION_TICKET_KEYS            0x03000001  // QUIC_TICKET_KEY_CONFIG[]
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
#define QUIC_PARAM_CONFIGURATION_VERSION_SETTINGS       0x03000002  // QUIC_VERSION_SETTINGS
#endif
// Schannel-specific Configuration parameter
typedef struct QUIC_SCHANNEL_CREDENTIAL_ATTRIBUTE_W {
    unsigned long Attribute;
    unsigned long BufferLength;
    void* Buffer;
} QUIC_SCHANNEL_CREDENTIAL_ATTRIBUTE_W;
#define QUIC_PARAM_CONFIGURATION_SCHANNEL_CREDENTIAL_ATTRIBUTE_W  0x03000003  // QUIC_SCHANNEL_CREDENTIAL_ATTRIBUTE_W

//
// Parameters for Listener.
//
#define QUIC_PARAM_LISTENER_LOCAL_ADDRESS               0x04000000  // QUIC_ADDR
#define QUIC_PARAM_LISTENER_STATS                       0x04000001  // QUIC_LISTENER_STATISTICS
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
#define QUIC_PARAM_LISTENER_CIBIR_ID                    0x04000002  // uint8_t[] {offset, id[]}
#define QUIC_PARAM_LISTENER_PARTITION_INDEX             0x04000005  // uint16_t
#endif
#define QUIC_PARAM_DOS_MODE_EVENTS                      0x04000004  // BOOLEAN

//
// Parameters for Connection.
//
#define QUIC_PARAM_CONN_QUIC_VERSION                    0x05000000  // uint32_t
#define QUIC_PARAM_CONN_LOCAL_ADDRESS                   0x05000001  // QUIC_ADDR
#define QUIC_PARAM_CONN_REMOTE_ADDRESS                  0x05000002  // QUIC_ADDR
#define QUIC_PARAM_CONN_IDEAL_PROCESSOR                 0x05000003  // uint16_t
#define QUIC_PARAM_CONN_SETTINGS                        0x05000004  // QUIC_SETTINGS
#define QUIC_PARAM_CONN_STATISTICS                      0x05000005  // QUIC_STATISTICS
#define QUIC_PARAM_CONN_STATISTICS_PLAT                 0x05000006  // QUIC_STATISTICS
#define QUIC_PARAM_CONN_SHARE_UDP_BINDING               0x05000007  // uint8_t (BOOLEAN)
#define QUIC_PARAM_CONN_LOCAL_BIDI_STREAM_COUNT         0x05000008  // uint16_t
#define QUIC_PARAM_CONN_LOCAL_UNIDI_STREAM_COUNT        0x05000009  // uint16_t
#define QUIC_PARAM_CONN_MAX_STREAM_IDS                  0x0500000A  // uint64_t[4]
#define QUIC_PARAM_CONN_CLOSE_REASON_PHRASE             0x0500000B  // char[]
#define QUIC_PARAM_CONN_STREAM_SCHEDULING_SCHEME        0x0500000C  // QUIC_STREAM_SCHEDULING_SCHEME
#define QUIC_PARAM_CONN_DATAGRAM_RECEIVE_ENABLED        0x0500000D  // uint8_t (BOOLEAN)
#define QUIC_PARAM_CONN_DATAGRAM_SEND_ENABLED           0x0500000E  // uint8_t (BOOLEAN)
#ifdef QUIC_API_ENABLE_INSECURE_FEATURES
#define QUIC_PARAM_CONN_DISABLE_1RTT_ENCRYPTION         0x0500000F  // uint8_t (BOOLEAN)
#endif
#define QUIC_PARAM_CONN_RESUMPTION_TICKET               0x05000010  // uint8_t[]
#define QUIC_PARAM_CONN_PEER_CERTIFICATE_VALID          0x05000011  // uint8_t (BOOLEAN)
#define QUIC_PARAM_CONN_LOCAL_INTERFACE                 0x05000012  // uint32_t
#define QUIC_PARAM_CONN_TLS_SECRETS                     0x05000013  // QUIC_TLS_SECRETS (SSLKEYLOGFILE compatible)
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
#define QUIC_PARAM_CONN_VERSION_SETTINGS                0x05000014  // QUIC_VERSION_SETTINGS
#define QUIC_PARAM_CONN_CIBIR_ID                        0x05000015  // uint8_t[] {offset, id[]}
#endif
#define QUIC_PARAM_CONN_STATISTICS_V2                   0x05000016  // QUIC_STATISTICS_V2
#define QUIC_PARAM_CONN_STATISTICS_V2_PLAT              0x05000017  // QUIC_STATISTICS_V2
#define QUIC_PARAM_CONN_ORIG_DEST_CID                   0x05000018  // uint8_t[]
#define QUIC_PARAM_CONN_SEND_DSCP                       0x05000019  // uint8_t
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
#define QUIC_PARAM_CONN_NETWORK_STATISTICS              0x05000020  // struct QUIC_NETWORK_STATISTICS
#define QUIC_PARAM_CONN_CLOSE_ASYNC                     0x0500001A  // uint8_t
#endif

//
// Parameters for TLS.
//
#define QUIC_PARAM_TLS_HANDSHAKE_INFO                   0x06000000  // QUIC_HANDSHAKE_INFO
#define QUIC_PARAM_TLS_NEGOTIATED_ALPN                  0x06000001  // uint8_t[] (max 255 bytes)

#ifdef WIN32 // Schannel specific TLS parameters
typedef struct QUIC_SCHANNEL_CONTEXT_ATTRIBUTE_W {
    unsigned long Attribute;
    void* Buffer;
} QUIC_SCHANNEL_CONTEXT_ATTRIBUTE_W;
#define QUIC_PARAM_TLS_SCHANNEL_CONTEXT_ATTRIBUTE_W     0x07000000  // QUIC_SCHANNEL_CONTEXT_ATTRIBUTE_W
typedef struct QUIC_SCHANNEL_CONTEXT_ATTRIBUTE_EX_W {
    unsigned long Attribute;
    unsigned long BufferLength;
    void* Buffer;
} QUIC_SCHANNEL_CONTEXT_ATTRIBUTE_EX_W;
#define QUIC_PARAM_TLS_SCHANNEL_CONTEXT_ATTRIBUTE_EX_W  0x07000001  // QUIC_SCHANNEL_CONTEXT_ATTRIBUTE_EX_W
#define QUIC_PARAM_TLS_SCHANNEL_SECURITY_CONTEXT_TOKEN  0x07000002  // HANDLE
#endif

//
// Parameters for Stream.
//
#define QUIC_PARAM_STREAM_ID                            0x08000000  // QUIC_UINT62
#define QUIC_PARAM_STREAM_0RTT_LENGTH                   0x08000001  // uint64_t
#define QUIC_PARAM_STREAM_IDEAL_SEND_BUFFER_SIZE        0x08000002  // uint64_t - bytes
#define QUIC_PARAM_STREAM_PRIORITY                      0x08000003  // uint16_t - 0 (low) to 0xFFFF (high) - 0x7FFF (default)
#define QUIC_PARAM_STREAM_STATISTICS                    0X08000004  // QUIC_STREAM_STATISTICS
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
#define QUIC_PARAM_STREAM_RELIABLE_OFFSET               0x08000005  // uint64_t
#endif

typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_SET_PARAM_FN)(
    _When_(QUIC_PARAM_IS_GLOBAL(Param), _Reserved_)
    _When_(!QUIC_PARAM_IS_GLOBAL(Param), _In_ _Pre_defensive_)
        HQUIC Handle,
    _In_ uint32_t Param,
    _In_ uint32_t BufferLength,
    _In_reads_bytes_(BufferLength)
        const void* Buffer
    );

typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_GET_PARAM_FN)(
    _When_(QUIC_PARAM_IS_GLOBAL(Param), _Reserved_)
    _When_(!QUIC_PARAM_IS_GLOBAL(Param), _In_ _Pre_defensive_)
        HQUIC Handle,
    _In_ uint32_t Param,
    _Inout_ _Pre_defensive_ uint32_t* BufferLength,
    _Out_writes_bytes_opt_(*BufferLength)
        void* Buffer
    );

//
// Registration Context Interface.
//

//
// Opens a new registration.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_REGISTRATION_OPEN_FN)(
    _In_opt_ const QUIC_REGISTRATION_CONFIG* Config,
    _Outptr_ _At_(*Registration, __drv_allocatesMem(Mem)) _Pre_defensive_
        HQUIC* Registration
    );

//
// Closes the registration. This function synchronizes the cleanup of all
// child objects. It does this by blocking until all those child objects have
// been closed by the application.
// N.B. This function will deadlock if called in any MsQuic callbacks.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
void
(QUIC_API * QUIC_REGISTRATION_CLOSE_FN)(
    _In_ _Pre_defensive_ __drv_freesMem(Mem)
        HQUIC Registration
    );

#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES

typedef
_Function_class_(QUIC_REGISTRATION_CLOSE_CALLBACK)
void
(QUIC_API QUIC_REGISTRATION_CLOSE_CALLBACK)(
    _In_opt_ void* Context
    );

typedef QUIC_REGISTRATION_CLOSE_CALLBACK *QUIC_REGISTRATION_CLOSE_CALLBACK_HANDLER;

//
// Closes the registration. This function synchronizes the cleanup of all child
// objects. The callback handler is invoked once all those child objects have
// been closed by the application.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
void
(QUIC_API * QUIC_REGISTRATION_CLOSE2_FN)(
    _In_ _Pre_defensive_ __drv_freesMem(Mem)
        HQUIC Registration,
    _In_ _Pre_defensive_ QUIC_REGISTRATION_CLOSE_CALLBACK_HANDLER Handler,
    _In_opt_ void* Context
    );

#endif // QUIC_API_ENABLE_PREVIEW_FEATURES

//
// Calls shutdown for all connections in this registration. Don't call on a
// MsQuic callback thread or it might deadlock.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
void
(QUIC_API * QUIC_REGISTRATION_SHUTDOWN_FN)(
    _In_ _Pre_defensive_ HQUIC Registration,
    _In_ QUIC_CONNECTION_SHUTDOWN_FLAGS Flags,
    _In_ _Pre_defensive_ QUIC_UINT62 ErrorCode // Application defined error code
    );

//
// Configuration Interface.
//

//
// Opens a new configuration.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_CONFIGURATION_OPEN_FN)(
    _In_ _Pre_defensive_ HQUIC Registration,
    _In_reads_(AlpnBufferCount) _Pre_defensive_
        const QUIC_BUFFER* const AlpnBuffers,
    _In_range_(>, 0) uint32_t AlpnBufferCount,
    _In_reads_bytes_opt_(SettingsSize)
        const QUIC_SETTINGS* Settings,
    _In_ uint32_t SettingsSize,
    _In_opt_ void* Context,
    _Outptr_ _At_(*Configuration, __drv_allocatesMem(Mem)) _Pre_defensive_
        HQUIC* Configuration
    );

//
// Closes an existing configuration.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
void
(QUIC_API * QUIC_CONFIGURATION_CLOSE_FN)(
    _In_ _Pre_defensive_ __drv_freesMem(Mem)
        HQUIC Configuration
    );

//
// Loads the credentials based on the input configuration.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_CONFIGURATION_LOAD_CREDENTIAL_FN)(
    _In_ _Pre_defensive_ HQUIC Configuration,
    _In_ _Pre_defensive_ const QUIC_CREDENTIAL_CONFIG* CredConfig
    );

//
// Listener Context Interface.
//

typedef enum QUIC_LISTENER_EVENT_TYPE {
    QUIC_LISTENER_EVENT_NEW_CONNECTION      = 0,
    QUIC_LISTENER_EVENT_STOP_COMPLETE       = 1,
    QUIC_LISTENER_EVENT_DOS_MODE_CHANGED    = 2,
} QUIC_LISTENER_EVENT_TYPE;

typedef struct QUIC_LISTENER_EVENT {
    QUIC_LISTENER_EVENT_TYPE Type;
    union {
        struct {
            const QUIC_NEW_CONNECTION_INFO* Info;
            HQUIC Connection;
        } NEW_CONNECTION;
        struct {
            BOOLEAN AppCloseInProgress  : 1;
            BOOLEAN RESERVED            : 7;
        } STOP_COMPLETE;
        struct {
            BOOLEAN DosModeEnabled : 1;
            BOOLEAN RESERVED       : 7;
        } DOS_MODE_CHANGED;
    };
} QUIC_LISTENER_EVENT;

typedef
_When_(
    Event->Type != QUIC_LISTENER_EVENT_DOS_MODE_CHANGED,
    _IRQL_requires_max_(PASSIVE_LEVEL))
_When_(
    Event->Type == QUIC_LISTENER_EVENT_DOS_MODE_CHANGED,
    _IRQL_requires_max_(DISPATCH_LEVEL))
_Function_class_(QUIC_LISTENER_CALLBACK)
QUIC_STATUS
(QUIC_API QUIC_LISTENER_CALLBACK)(
    _In_ HQUIC Listener,
    _In_opt_ void* Context,
    _Inout_ QUIC_LISTENER_EVENT* Event
    );

typedef QUIC_LISTENER_CALLBACK *QUIC_LISTENER_CALLBACK_HANDLER;

//
// Opens a new listener.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_LISTENER_OPEN_FN)(
    _In_ _Pre_defensive_ HQUIC Registration,
    _In_ _Pre_defensive_ QUIC_LISTENER_CALLBACK_HANDLER Handler,
    _In_opt_ void* Context,
    _Outptr_ _At_(*Listener, __drv_allocatesMem(Mem)) _Pre_defensive_
        HQUIC* Listener
    );

//
// Closes an existing listener.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
void
(QUIC_API * QUIC_LISTENER_CLOSE_FN)(
    _In_ _Pre_defensive_ __drv_freesMem(Mem)
        HQUIC Listener
    );

//
// Starts the listener processing incoming connections.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_LISTENER_START_FN)(
    _In_ _Pre_defensive_ HQUIC Listener,
    _In_reads_(AlpnBufferCount) _Pre_defensive_
        const QUIC_BUFFER* const AlpnBuffers,
    _In_range_(>, 0) uint32_t AlpnBufferCount,
    _In_opt_ const QUIC_ADDR* LocalAddress
    );

//
// Asynchronously stops the listener from processing incoming connections.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
void
(QUIC_API * QUIC_LISTENER_STOP_FN)(
    _In_ _Pre_defensive_ HQUIC Listener
    );

//
// Connections
//

typedef enum QUIC_CONNECTION_EVENT_TYPE {
    QUIC_CONNECTION_EVENT_CONNECTED                         = 0,
    QUIC_CONNECTION_EVENT_SHUTDOWN_INITIATED_BY_TRANSPORT   = 1,    // The transport started the shutdown process.
    QUIC_CONNECTION_EVENT_SHUTDOWN_INITIATED_BY_PEER        = 2,    // The peer application started the shutdown process.
    QUIC_CONNECTION_EVENT_SHUTDOWN_COMPLETE                 = 3,    // Ready for the handle to be closed.
    QUIC_CONNECTION_EVENT_LOCAL_ADDRESS_CHANGED             = 4,
    QUIC_CONNECTION_EVENT_PEER_ADDRESS_CHANGED              = 5,
    QUIC_CONNECTION_EVENT_PEER_STREAM_STARTED               = 6,
    QUIC_CONNECTION_EVENT_STREAMS_AVAILABLE                 = 7,
    QUIC_CONNECTION_EVENT_PEER_NEEDS_STREAMS                = 8,
    QUIC_CONNECTION_EVENT_IDEAL_PROCESSOR_CHANGED           = 9,
    QUIC_CONNECTION_EVENT_DATAGRAM_STATE_CHANGED            = 10,
    QUIC_CONNECTION_EVENT_DATAGRAM_RECEIVED                 = 11,
    QUIC_CONNECTION_EVENT_DATAGRAM_SEND_STATE_CHANGED       = 12,
    QUIC_CONNECTION_EVENT_RESUMED                           = 13,   // Server-only; provides resumption data, if any.
    QUIC_CONNECTION_EVENT_RESUMPTION_TICKET_RECEIVED        = 14,   // Client-only; provides ticket to persist, if any.
    QUIC_CONNECTION_EVENT_PEER_CERTIFICATE_RECEIVED         = 15,   // Only with QUIC_CREDENTIAL_FLAG_INDICATE_CERTIFICATE_RECEIVED set
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
    QUIC_CONNECTION_EVENT_RELIABLE_RESET_NEGOTIATED         = 16,   // Only indicated if QUIC_SETTINGS.ReliableResetEnabled is TRUE.
    QUIC_CONNECTION_EVENT_ONE_WAY_DELAY_NEGOTIATED          = 17,   // Only indicated if QUIC_SETTINGS.OneWayDelayEnabled is TRUE.
    QUIC_CONNECTION_EVENT_NETWORK_STATISTICS                = 18,   // Only indicated if QUIC_SETTINGS.EnableNetStatsEvent is TRUE.
#endif
} QUIC_CONNECTION_EVENT_TYPE;

typedef struct QUIC_CONNECTION_EVENT {
    QUIC_CONNECTION_EVENT_TYPE Type;
    union {
        struct {
            BOOLEAN SessionResumed;
            _Field_range_(>, 0)
            uint8_t NegotiatedAlpnLength;
            _Field_size_(NegotiatedAlpnLength)
            const uint8_t* NegotiatedAlpn;
        } CONNECTED;
        struct {
            QUIC_STATUS Status;
            QUIC_UINT62 ErrorCode; // Wire format error code.
        } SHUTDOWN_INITIATED_BY_TRANSPORT;
        struct {
            QUIC_UINT62 ErrorCode;
        } SHUTDOWN_INITIATED_BY_PEER;
        struct {
            BOOLEAN HandshakeCompleted          : 1;
            BOOLEAN PeerAcknowledgedShutdown    : 1;
            BOOLEAN AppCloseInProgress          : 1;
        } SHUTDOWN_COMPLETE;
        struct {
            const QUIC_ADDR* Address;
        } LOCAL_ADDRESS_CHANGED;
        struct {
            const QUIC_ADDR* Address;
        } PEER_ADDRESS_CHANGED;
        struct {
            HQUIC Stream;
            QUIC_STREAM_OPEN_FLAGS Flags;
        } PEER_STREAM_STARTED;
        struct {
            uint16_t BidirectionalCount;
            uint16_t UnidirectionalCount;
        } STREAMS_AVAILABLE;
        struct {
            BOOLEAN Bidirectional;
        } PEER_NEEDS_STREAMS;
        struct {
            uint16_t IdealProcessor;
            uint16_t PartitionIndex;
        } IDEAL_PROCESSOR_CHANGED;
        struct {
            BOOLEAN SendEnabled;
            uint16_t MaxSendLength;
        } DATAGRAM_STATE_CHANGED;
        struct {
            const QUIC_BUFFER* Buffer;
            QUIC_RECEIVE_FLAGS Flags;
        } DATAGRAM_RECEIVED;
        struct {
            /* inout */ void* ClientContext;
            QUIC_DATAGRAM_SEND_STATE State;
        } DATAGRAM_SEND_STATE_CHANGED;
        struct {
            uint16_t ResumptionStateLength;
            const uint8_t* ResumptionState;
        } RESUMED;
        struct {
            _Field_range_(>, 0)
            uint32_t ResumptionTicketLength;
            _Field_size_(ResumptionTicketLength)
            const uint8_t* ResumptionTicket;
        } RESUMPTION_TICKET_RECEIVED;
        struct {
            QUIC_CERTIFICATE* Certificate;      // Peer certificate (platform specific). Valid only during QUIC_CONNECTION_EVENT_PEER_CERTIFICATE_RECEIVED callback.
            uint32_t DeferredErrorFlags;        // Bit flag of errors (only valid with QUIC_CREDENTIAL_FLAG_DEFER_CERTIFICATE_VALIDATION) - Schannel only, zero otherwise.
            QUIC_STATUS DeferredStatus;         // Most severe error status (only valid with QUIC_CREDENTIAL_FLAG_DEFER_CERTIFICATE_VALIDATION)
            QUIC_CERTIFICATE_CHAIN* Chain;      // Peer certificate chain (platform specific). Valid only during QUIC_CONNECTION_EVENT_PEER_CERTIFICATE_RECEIVED callback.
        } PEER_CERTIFICATE_RECEIVED;
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
        struct {
            BOOLEAN IsNegotiated;
        } RELIABLE_RESET_NEGOTIATED;
        struct {
            BOOLEAN SendNegotiated;             // TRUE if sending one-way delay timestamps is negotiated.
            BOOLEAN ReceiveNegotiated;          // TRUE if receiving one-way delay timestamps is negotiated.
        } ONE_WAY_DELAY_NEGOTIATED;
        QUIC_NETWORK_STATISTICS NETWORK_STATISTICS;
#endif
    };
} QUIC_CONNECTION_EVENT;

typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
_Function_class_(QUIC_CONNECTION_CALLBACK)
QUIC_STATUS
(QUIC_API QUIC_CONNECTION_CALLBACK)(
    _In_ HQUIC Connection,
    _In_opt_ void* Context,
    _Inout_ QUIC_CONNECTION_EVENT* Event
    );

typedef QUIC_CONNECTION_CALLBACK *QUIC_CONNECTION_CALLBACK_HANDLER;

//
// Opens a new connection.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_CONNECTION_OPEN_FN)(
    _In_ _Pre_defensive_ HQUIC Registration,
    _In_ _Pre_defensive_ QUIC_CONNECTION_CALLBACK_HANDLER Handler,
    _In_opt_ void* Context,
    _Outptr_ _At_(*Connection, __drv_allocatesMem(Mem)) _Pre_defensive_
        HQUIC* Connection
    );
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_CONNECTION_OPEN_IN_PARTITION_FN)(
    _In_ _Pre_defensive_ HQUIC Registration,
    _In_ uint16_t PartitionIndex,
    _In_ _Pre_defensive_ QUIC_CONNECTION_CALLBACK_HANDLER Handler,
    _In_opt_ void* Context,
    _Outptr_ _At_(*Connection, __drv_allocatesMem(Mem)) _Pre_defensive_
        HQUIC* Connection
    );

//
// Closes an existing connection.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
void
(QUIC_API * QUIC_CONNECTION_CLOSE_FN)(
    _In_ _Pre_defensive_ __drv_freesMem(Mem)
        HQUIC Connection
    );

//
// Starts the shutdown process on the connection. This immediately and silently
// shuts down any open streams; which will trigger callbacks for
// QUIC_CONNECTION_EVENT_STREAM_CLOSED events. Does nothing if already shutdown.
// Can be passed either a connection or stream handle.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
void
(QUIC_API * QUIC_CONNECTION_SHUTDOWN_FN)(
    _In_ _Pre_defensive_ HQUIC Connection,
    _In_ QUIC_CONNECTION_SHUTDOWN_FLAGS Flags,
    _In_ _Pre_defensive_ QUIC_UINT62 ErrorCode // Application defined error code
    );

//
// Uses the QUIC (client) handle to start a connection attempt to the
// remote server. Can be passed either a connection or stream handle.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_CONNECTION_START_FN)(
    _In_ _Pre_defensive_ HQUIC Connection,
    _In_ _Pre_defensive_ HQUIC Configuration,
    _In_ QUIC_ADDRESS_FAMILY Family,
    _In_reads_or_z_opt_(QUIC_MAX_SNI_LENGTH)
        const char* ServerName,
    _In_ uint16_t ServerPort // Host byte order
    );

//
// Sets the (server-side) configuration handle for the connection. This must be
// called on an accepted connection in order to proceed with the QUIC handshake.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_CONNECTION_SET_CONFIGURATION_FN)(
    _In_ _Pre_defensive_ HQUIC Connection,
    _In_ _Pre_defensive_ HQUIC Configuration
    );

//
// Uses the QUIC (server) handle to send a resumption ticket to the remote
// client, optionally with app-specific data useful during resumption.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_CONNECTION_SEND_RESUMPTION_FN)(
    _In_ _Pre_defensive_ HQUIC Connection,
    _In_ QUIC_SEND_RESUMPTION_FLAGS Flags,
    _In_ uint16_t DataLength,
    _In_reads_bytes_opt_(DataLength)
        const uint8_t* ResumptionData
    );

//
// Uses the QUIC (server) handle to complete resumption ticket validation.
// This must be called after server app handles ticket validation and then
// return QUIC_STATUS_PENDING.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_CONNECTION_COMP_RESUMPTION_FN)(
    _In_ _Pre_defensive_ HQUIC Connection,
    _In_ BOOLEAN Result
    );

//
// Uses the QUIC (client) handle to complete certificate validation.
// This must be called after client app handles certificate validation
// and then return QUIC_STATUS_PENDING. The TlsAlert value is ignored if Result
// equals TRUE (recommend just pass QUIC_TLS_ALERT_CODE_SUCCESS).
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_CONNECTION_COMP_CERT_FN)(
    _In_ _Pre_defensive_ HQUIC Connection,
    _In_ BOOLEAN Result,
    _In_ QUIC_TLS_ALERT_CODES TlsAlert
    );

//
// Streams
//

typedef enum QUIC_STREAM_EVENT_TYPE {
    QUIC_STREAM_EVENT_START_COMPLETE            = 0,
    QUIC_STREAM_EVENT_RECEIVE                   = 1,
    QUIC_STREAM_EVENT_SEND_COMPLETE             = 2,
    QUIC_STREAM_EVENT_PEER_SEND_SHUTDOWN        = 3,
    QUIC_STREAM_EVENT_PEER_SEND_ABORTED         = 4,
    QUIC_STREAM_EVENT_PEER_RECEIVE_ABORTED      = 5,
    QUIC_STREAM_EVENT_SEND_SHUTDOWN_COMPLETE    = 6,
    QUIC_STREAM_EVENT_SHUTDOWN_COMPLETE         = 7,
    QUIC_STREAM_EVENT_IDEAL_SEND_BUFFER_SIZE    = 8,
    QUIC_STREAM_EVENT_PEER_ACCEPTED             = 9,
    QUIC_STREAM_EVENT_CANCEL_ON_LOSS            = 10,
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
    QUIC_STREAM_EVENT_RECEIVE_BUFFER_NEEDED = 11,
#endif
} QUIC_STREAM_EVENT_TYPE;

typedef struct QUIC_STREAM_EVENT {
    QUIC_STREAM_EVENT_TYPE Type;
    union {
        struct {
            QUIC_STATUS Status;
            QUIC_UINT62 ID;
            BOOLEAN PeerAccepted : 1;
            BOOLEAN RESERVED : 7;
        } START_COMPLETE;
        struct {
            /* in */    uint64_t AbsoluteOffset;
            /* inout */ uint64_t TotalBufferLength;
            _Field_size_(BufferCount)
            /* in */    const QUIC_BUFFER* Buffers;
            _Field_range_(0, UINT32_MAX)
            /* in */    uint32_t BufferCount;
            /* in */    QUIC_RECEIVE_FLAGS Flags;
        } RECEIVE;
        struct {
            BOOLEAN Canceled;
            void* ClientContext;
        } SEND_COMPLETE;
        struct {
            QUIC_UINT62 ErrorCode;
        } PEER_SEND_ABORTED;
        struct {
            QUIC_UINT62 ErrorCode;
        } PEER_RECEIVE_ABORTED;
        struct {
            BOOLEAN Graceful;
        } SEND_SHUTDOWN_COMPLETE;
        struct {
            BOOLEAN ConnectionShutdown;
            BOOLEAN AppCloseInProgress       : 1;
            BOOLEAN ConnectionShutdownByApp  : 1;
            BOOLEAN ConnectionClosedRemotely : 1;
            BOOLEAN RESERVED                 : 5;
            QUIC_UINT62 ConnectionErrorCode;
            QUIC_STATUS ConnectionCloseStatus;
        } SHUTDOWN_COMPLETE;
        struct {
            uint64_t ByteCount;
        } IDEAL_SEND_BUFFER_SIZE;
        struct {
            /* out */ QUIC_UINT62 ErrorCode;
        } CANCEL_ON_LOSS;
#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
        struct {
            /* in */  uint64_t BufferLengthNeeded;
        } RECEIVE_BUFFER_NEEDED;
#endif
    };
} QUIC_STREAM_EVENT;

typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
_Function_class_(QUIC_STREAM_CALLBACK)
QUIC_STATUS
(QUIC_API QUIC_STREAM_CALLBACK)(
    _In_ HQUIC Stream,
    _In_opt_ void* Context,
    _Inout_ QUIC_STREAM_EVENT* Event
    );

typedef QUIC_STREAM_CALLBACK *QUIC_STREAM_CALLBACK_HANDLER;

//
// Opens a stream on the given connection.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_STREAM_OPEN_FN)(
    _In_ _Pre_defensive_ HQUIC Connection,
    _In_ QUIC_STREAM_OPEN_FLAGS Flags,
    _In_ _Pre_defensive_ QUIC_STREAM_CALLBACK_HANDLER Handler,
    _In_opt_ void* Context,
    _Outptr_ _At_(*Stream, __drv_allocatesMem(Mem)) _Pre_defensive_
        HQUIC* Stream
    );

//
// Closes a stream handle.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
void
(QUIC_API * QUIC_STREAM_CLOSE_FN)(
    _In_ _Pre_defensive_ __drv_freesMem(Mem)
        HQUIC Stream
    );

//
// Starts processing the stream.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_STREAM_START_FN)(
    _In_ _Pre_defensive_ HQUIC Stream,
    _In_ QUIC_STREAM_START_FLAGS Flags
    );

//
// Shuts the stream down as specified, and waits for graceful
// shutdowns to complete. Does nothing if already shut down.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_STREAM_SHUTDOWN_FN)(
    _In_ _Pre_defensive_ HQUIC Stream,
    _In_ QUIC_STREAM_SHUTDOWN_FLAGS Flags,
    _In_ _Pre_defensive_ QUIC_UINT62 ErrorCode // Application defined error code
    );

//
// Sends data on an open stream.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_STREAM_SEND_FN)(
    _In_ _Pre_defensive_ HQUIC Stream,
    _In_reads_(BufferCount) _Pre_defensive_
        const QUIC_BUFFER* const Buffers,
    _In_ uint32_t BufferCount,
    _In_ QUIC_SEND_FLAGS Flags,
    _In_opt_ void* ClientSendContext
    );

//
// Completes a previously pended receive callback.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
void
(QUIC_API * QUIC_STREAM_RECEIVE_COMPLETE_FN)(
    _In_ _Pre_defensive_ HQUIC Stream,
    _In_ uint64_t BufferLength
    );

//
// Enables or disables stream receive callbacks.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_STREAM_RECEIVE_SET_ENABLED_FN)(
    _In_ _Pre_defensive_ HQUIC Stream,
    _In_ BOOLEAN IsEnabled
    );

#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
//
// Provides receive buffers to the stream.
// The buffers are owned by the caller and must remain valid until a receive
// indication for all bytes in the buffer, or the stream is closed.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_STREAM_PROVIDE_RECEIVE_BUFFERS_FN)(
    _In_ _Pre_defensive_ HQUIC Stream,
    _In_ uint32_t BufferCount,
    _In_reads_(BufferCount) const QUIC_BUFFER* Buffers
    );

#endif

//
// Datagrams
//

//
// Sends an unreliable datagram on the connection. Note, the total payload
// of the send must fit in a single QUIC packet.
//
typedef
_IRQL_requires_max_(DISPATCH_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_DATAGRAM_SEND_FN)(
    _In_ _Pre_defensive_ HQUIC Connection,
    _In_reads_(BufferCount) _Pre_defensive_
        const QUIC_BUFFER* const Buffers,
    _In_ uint32_t BufferCount,
    _In_ QUIC_SEND_FLAGS Flags,
    _In_opt_ void* ClientSendContext
    );

//
// Connection Pool API
//

#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES

typedef enum QUIC_CONNECTION_POOL_FLAGS {
    QUIC_CONNECTION_POOL_FLAG_NONE =                            0x00000000,
    QUIC_CONNECTION_POOL_FLAG_CLOSE_ON_FAILURE =                0x00000001,
} QUIC_CONNECTION_POOL_FLAGS;

DEFINE_ENUM_FLAG_OPERATORS(QUIC_CONNECTION_POOL_FLAGS);

typedef struct QUIC_CONNECTION_POOL_CONFIG {
    HQUIC Registration;
    HQUIC Configuration;
    QUIC_CONNECTION_CALLBACK_HANDLER Handler;
    _Field_size_opt_(NumberOfConnections)
        void** Context;                         // Optional
    _Field_z_ const char* ServerName;
    const QUIC_ADDR* ServerAddress;             // Optional
    QUIC_ADDRESS_FAMILY Family;
    uint16_t ServerPort;
    uint16_t NumberOfConnections;
    _At_buffer_(_Curr_, _Iter_, NumberOfConnections, _Field_size_(CibirIdLength))
    _Field_size_opt_(NumberOfConnections)
        uint8_t** CibirIds;                     // Optional
    uint8_t CibirIdLength;                      // Zero if not using CIBIR
    QUIC_CONNECTION_POOL_FLAGS Flags;
} QUIC_CONNECTION_POOL_CONFIG;

//
// Creates a simple pool of NumberOfConnections connections, all with the same
// Handler, and puts them in the caller-supplied array.
// Connections are spread evenly across RSS CPUs as much as possible.
// If NumberOfConnections is more than the number of RSS cores, then multiple
// connections will be put on the same CPU.
//
typedef
_IRQL_requires_max_(PASSIVE_LEVEL)
QUIC_STATUS
(QUIC_API * QUIC_CONN_POOL_CREATE_FN)(
    _In_ QUIC_CONNECTION_POOL_CONFIG* Config,
    _Out_writes_(Config->NumberOfConnections)
        HQUIC* ConnectionPool
    );

#endif // QUIC_API_ENABLE_PREVIEW_FEATURES

//
// Version 2 API Function Table. Returned from MsQuicOpenVersion when Version
// is 2. Also returned from MsQuicOpen2.
//
typedef struct QUIC_API_TABLE {

    QUIC_SET_CONTEXT_FN                 SetContext;
    QUIC_GET_CONTEXT_FN                 GetContext;
    QUIC_SET_CALLBACK_HANDLER_FN        SetCallbackHandler;

    QUIC_SET_PARAM_FN                   SetParam;
    QUIC_GET_PARAM_FN                   GetParam;

    QUIC_REGISTRATION_OPEN_FN           RegistrationOpen;
    QUIC_REGISTRATION_CLOSE_FN          RegistrationClose;
    QUIC_REGISTRATION_SHUTDOWN_FN       RegistrationShutdown;

    QUIC_CONFIGURATION_OPEN_FN          ConfigurationOpen;
    QUIC_CONFIGURATION_CLOSE_FN         ConfigurationClose;
    QUIC_CONFIGURATION_LOAD_CREDENTIAL_FN
                                        ConfigurationLoadCredential;

    QUIC_LISTENER_OPEN_FN               ListenerOpen;
    QUIC_LISTENER_CLOSE_FN              ListenerClose;
    QUIC_LISTENER_START_FN              ListenerStart;
    QUIC_LISTENER_STOP_FN               ListenerStop;

    QUIC_CONNECTION_OPEN_FN             ConnectionOpen;
    QUIC_CONNECTION_CLOSE_FN            ConnectionClose;
    QUIC_CONNECTION_SHUTDOWN_FN         ConnectionShutdown;
    QUIC_CONNECTION_START_FN            ConnectionStart;
    QUIC_CONNECTION_SET_CONFIGURATION_FN
                                        ConnectionSetConfiguration;
    QUIC_CONNECTION_SEND_RESUMPTION_FN  ConnectionSendResumptionTicket;

    QUIC_STREAM_OPEN_FN                 StreamOpen;
    QUIC_STREAM_CLOSE_FN                StreamClose;
    QUIC_STREAM_START_FN                StreamStart;
    QUIC_STREAM_SHUTDOWN_FN             StreamShutdown;
    QUIC_STREAM_SEND_FN                 StreamSend;
    QUIC_STREAM_RECEIVE_COMPLETE_FN     StreamReceiveComplete;
    QUIC_STREAM_RECEIVE_SET_ENABLED_FN  StreamReceiveSetEnabled;

    QUIC_DATAGRAM_SEND_FN               DatagramSend;

    QUIC_CONNECTION_COMP_RESUMPTION_FN  ConnectionResumptionTicketValidationComplete; // Available from v2.2
    QUIC_CONNECTION_COMP_CERT_FN        ConnectionCertificateValidationComplete;      // Available from v2.2

    QUIC_CONNECTION_OPEN_IN_PARTITION_FN
                                        ConnectionOpenInPartition;   // Available from v2.5

#ifdef QUIC_API_ENABLE_PREVIEW_FEATURES
    QUIC_STREAM_PROVIDE_RECEIVE_BUFFERS_FN
                                        StreamProvideReceiveBuffers; // Available from v2.5

    QUIC_CONN_POOL_CREATE_FN            ConnectionPoolCreate;        // Available from v2.5

#ifndef _KERNEL_MODE
#define QUIC_API_EXECUTION_CONTEXT
    QUIC_EXECUTION_CREATE_FN            ExecutionCreate;    // Available from v2.5
    QUIC_EXECUTION_DELETE_FN            ExecutionDelete;    // Available from v2.5
    QUIC_EXECUTION_POLL_FN              ExecutionPoll;      // Available from v2.5
#endif // _KERNEL_MODE
    QUIC_REGISTRATION_CLOSE2_FN         RegistrationClose2; // Available from v2.6
#endif // QUIC_API_ENABLE_PREVIEW_FEATURES

} QUIC_API_TABLE;

#define QUIC_API_VERSION_1      1 // Not supported any more
#define QUIC_API_VERSION_2      2 // Current latest

#if defined(_KERNEL_MODE) && !defined(_WIN64)

//
// 32 bit kernel mode is no longer supported, so shim behavior in 32 bit kernel
// mode
//
#define MsQuicClose(QuicApi) UNREFERENCED_PARAMETER((QuicApi))
#define MsQuicOpenVersion(Version, QuicApi) QUIC_STATUS_NOT_SUPPORTED

#else

//
// Opens the API library and initializes it if this is the first call for the
// process. It returns API function table for the rest of the API's functions.
// MsQuicClose must be called when the app is done with the function table.
//
_IRQL_requires_max_(PASSIVE_LEVEL)
_Check_return_
#if (__cplusplus >= 201703L || _MSVC_LANG >= 201703L)
[[nodiscard]]
#endif
QUIC_STATUS
QUIC_API
MsQuicOpenVersion(
    _In_ uint32_t Version,
    _Out_ _Pre_defensive_ const void** QuicApi
    );

//
// Cleans up the function table returned from MsQuicOpenVersion and releases the
// reference on the API.
//
_IRQL_requires_max_(PASSIVE_LEVEL)
void
QUIC_API
MsQuicClose(
    _In_ _Pre_defensive_ const void* QuicApi
    );

#endif

_IRQL_requires_max_(PASSIVE_LEVEL)
_Check_return_
typedef
QUIC_STATUS
(QUIC_API *MsQuicOpenVersionFn)(
    _In_ uint32_t Version,
    _Out_ _Pre_defensive_ const void** QuicApi
    );

_IRQL_requires_max_(PASSIVE_LEVEL)
typedef
void
(QUIC_API *MsQuicCloseFn)(
    _In_ _Pre_defensive_ const void* QuicApi
    );

#ifdef _KERNEL_MODE

DECLSPEC_SELECTANY GUID MSQUIC_NPI_ID = {
    0xC43138E3, 0xCD13, 0x4CB1, { 0x9C, 0xAE, 0xE0, 0x05, 0xC8, 0x55, 0x7A, 0xBA }
}; // C43138E3-CD13-4CB1-9CAE-E005C8557ABA

DECLSPEC_SELECTANY GUID MSQUIC_MODULE_ID = {
    0x698F7C72, 0xC2E6, 0x49CD, { 0x8C, 0x39, 0x98, 0x85, 0x1D, 0x50, 0x19, 0x01 }
}; // 698F7C72-C2E6-49CD-8C39-98851D501901

typedef struct MSQUIC_NMR_DISPATCH {
    uint16_t  Version;
    uint16_t  Reserved;
    MsQuicOpenVersionFn OpenVersion;
    MsQuicCloseFn Close;
} MSQUIC_NMR_DISPATCH;

//
// Stores the internal NMR client state. It's meant to be opaque to the users.
//
typedef struct __MSQUIC_NMR_CLIENT {
    NPI_CLIENT_CHARACTERISTICS NpiClientCharacteristics;
    LONG BindingCount;
    HANDLE NmrClientHandle;
    NPI_MODULEID ModuleId;
    KEVENT RegistrationCompleteEvent;
    MSQUIC_NMR_DISPATCH* ProviderDispatch;
    BOOLEAN Deleting;
} __MSQUIC_NMR_CLIENT;

#define QUIC_GET_DISPATCH(h) (((__MSQUIC_NMR_CLIENT*)(h))->ProviderDispatch)

static
NTSTATUS
__MsQuicClientAttachProvider(
    _In_ HANDLE NmrBindingHandle,
    _In_ void *ClientContext,
    _In_ const NPI_REGISTRATION_INSTANCE *ProviderRegistrationInstance
    )
{
    UNREFERENCED_PARAMETER(ProviderRegistrationInstance);

    NTSTATUS Status;
    __MSQUIC_NMR_CLIENT* Client = (__MSQUIC_NMR_CLIENT*)ClientContext;
    void* ProviderContext;

    if (InterlockedIncrement(&Client->BindingCount) == 1) {
        #pragma warning(suppress:6387) // _Param_(2) could be '0' - by design.
        Status =
            NmrClientAttachProvider(
                NmrBindingHandle,
                Client,
                NULL,
                &ProviderContext,
                (const void**)&Client->ProviderDispatch);
        if (NT_SUCCESS(Status)) {
            KeSetEvent(&Client->RegistrationCompleteEvent, IO_NO_INCREMENT, FALSE);
        } else {
            InterlockedDecrement(&Client->BindingCount);
        }
    } else {
        Status = STATUS_NOINTERFACE;
    }

    return Status;
}

static
NTSTATUS
__MsQuicClientDetachProvider(
    _In_ void *ClientBindingContext
    )
{
    __MSQUIC_NMR_CLIENT* Client = (__MSQUIC_NMR_CLIENT*)ClientBindingContext;
    if (InterlockedOr8((char*)&Client->Deleting, 1)) {
        return STATUS_SUCCESS;
    } else {
        return STATUS_PENDING;
    }
}

_IRQL_requires_max_(PASSIVE_LEVEL)
__forceinline
void
MsQuicNmrClientDeregister(
    _Inout_ HANDLE* ClientHandle
    )
{
    __MSQUIC_NMR_CLIENT* Client = (__MSQUIC_NMR_CLIENT*)(*ClientHandle);

    if (InterlockedOr8((char*)&Client->Deleting, 1)) {
        //
        // We are already in the middle of detaching the client.
        // Complete it now.
        //
        NmrClientDetachProviderComplete(Client->NmrClientHandle);
    }

    if (Client->NmrClientHandle) {
        if (NmrDeregisterClient(Client->NmrClientHandle) == STATUS_PENDING) {
            //
            // Wait for the deregistration to complete.
            //
            NmrWaitForClientDeregisterComplete(Client->NmrClientHandle);
        }
        Client->NmrClientHandle = NULL;
    }

    ExFreePoolWithTag(Client, 'cNQM');
    *ClientHandle = NULL;
}

_IRQL_requires_max_(PASSIVE_LEVEL)
__forceinline
NTSTATUS
MsQuicNmrClientRegister(
    _Out_ HANDLE* ClientHandle,
    _In_ GUID* ClientModuleId,
    _In_ ULONG TimeoutMs // zero = no wait, non-zero = some wait
    )
{
    NPI_REGISTRATION_INSTANCE *ClientRegistrationInstance;
    NTSTATUS Status = STATUS_SUCCESS;

    __MSQUIC_NMR_CLIENT* Client =
        (__MSQUIC_NMR_CLIENT*)ExAllocatePool2(POOL_FLAG_NON_PAGED, sizeof(*Client), 'cNQM');
    if (Client == NULL) {
        Status = STATUS_INSUFFICIENT_RESOURCES;
        goto Exit;
    }

    KeInitializeEvent(&Client->RegistrationCompleteEvent, SynchronizationEvent, FALSE);

    Client->ModuleId.Length = sizeof(Client->ModuleId);
    Client->ModuleId.Type = MIT_GUID;
    Client->ModuleId.Guid = *ClientModuleId;

    Client->NpiClientCharacteristics.Length = sizeof(Client->NpiClientCharacteristics);
    Client->NpiClientCharacteristics.ClientAttachProvider = __MsQuicClientAttachProvider;
    Client->NpiClientCharacteristics.ClientDetachProvider = __MsQuicClientDetachProvider;

    ClientRegistrationInstance = &Client->NpiClientCharacteristics.ClientRegistrationInstance;
    ClientRegistrationInstance->Size = sizeof(*ClientRegistrationInstance);
    ClientRegistrationInstance->Version = 0;
    ClientRegistrationInstance->NpiId = &MSQUIC_NPI_ID;
    ClientRegistrationInstance->ModuleId = &Client->ModuleId;

    Status =
        NmrRegisterClient(
            &Client->NpiClientCharacteristics, Client, &Client->NmrClientHandle);
    if (!NT_SUCCESS(Status)) {
        goto Exit;
    }

    LARGE_INTEGER Timeout;
    Timeout.QuadPart = UInt32x32To64(TimeoutMs, 10000);
    Timeout.QuadPart = -Timeout.QuadPart;

    Status =
        KeWaitForSingleObject(
            &Client->RegistrationCompleteEvent,
            Executive, KernelMode, FALSE,
            &Timeout);
    if (Status != STATUS_SUCCESS) {
        Status = STATUS_UNSUCCESSFUL;
        goto Exit;
    }

    *ClientHandle = Client;

Exit:
    if (!NT_SUCCESS(Status) && Client != NULL) {
        MsQuicNmrClientDeregister((HANDLE*)&Client);
    }

    return Status;
}

#endif

//
// Version specific helpers that wrap MsQuicOpenVersion.
//

#if defined(__cplusplus)

_IRQL_requires_max_(PASSIVE_LEVEL)
_Check_return_
#if (__cplusplus >= 201703L || _MSVC_LANG >= 201703L)
[[nodiscard]]
#endif
#ifdef WIN32
__forceinline
#else
__attribute__((always_inline)) QUIC_INLINE
#endif
QUIC_STATUS
MsQuicOpen2(
    _Out_ _Pre_defensive_ const QUIC_API_TABLE** QuicApi
    )
{
    return MsQuicOpenVersion(QUIC_API_VERSION_2, (const void**)QuicApi);
}

#else

#define MsQuicOpen2(QuicApi) MsQuicOpenVersion(2, (const void**)QuicApi)

#endif // defined(__cplusplus)

#if defined(__cplusplus)
}
#endif

#endif // _MSQUIC_