rustls 0.24.0-dev.1

#![expect(missing_docs)]
//! <https://langsec.org> cat says:
//!
//! ```text
//!  ___ _   _ _    _      ___ ___ ___ ___   ___ _  _ ___ _____ ___ ___  _  _
//! | __| | | | |  | |    | _ \ __/ __/ _ \ / __| \| |_ _|_   _|_ _/ _ \| \| |
//! | _|| |_| | |__| |__  |   / _| (_| (_) | (_ | .` || |  | |  | | (_) | .` |
//! |_|  \___/|____|____| |_|_\___\___\___/ \___|_|\_|___| |_| |___\___/|_|\_|
//!
//!
//!                      .__....._             _.....__,
//!                        .": o :':         ;': o :".
//!                        `. `-' .'.       .'. `-' .'
//!                          `---'             `---'
//!
//!                _...----...      ...   ...      ...----..._
//!             .-'__..-""'----    `.  `"`  .'    ----'""-..__`-.
//!            '.-'   _.--"""'       `-._.-'       '"""--._   `-.`
//!            '  .-"'                  :                  `"-.  `
//!              '   `.              _.'"'._              .'   `
//!                    `.       ,.-'"       "'-.,       .'
//!                      `.                           .'
//!                        `-._                   _.-'
//!                            `"'--...___...--'"`
//!
//!  ___ ___ ___ ___  ___ ___   ___ ___  ___   ___ ___ ___ ___ ___ _  _  ___
//! | _ ) __| __/ _ \| _ \ __| | _ \ _ \/ _ \ / __| __/ __/ __|_ _| \| |/ __|
//! | _ \ _|| _| (_) |   / _|  |  _/   / (_) | (__| _|\__ \__ \| || .` | (_ |
//! |___/___|_| \___/|_|_\___| |_| |_|_\\___/ \___|___|___/___/___|_|\_|\___|
//! ```
//!
//! <https://langsec.org/ForWantOfANail-h2hc2014.pdf>

use alloc::boxed::Box;
use alloc::vec::Vec;

use crate::crypto::cipher::{EncodedMessage, MessageError, Payload};
use crate::enums::{ContentType, ContentTypeName, HandshakeType, ProtocolVersion};
use crate::error::{AlertDescription, InvalidMessage};
use crate::verify::DigitallySignedStruct;

#[macro_use]
mod macros;

mod client_hello;
pub(crate) use client_hello::{
    CertificateStatusRequest, ClientExtensions, ClientHelloPayload, ClientSessionTicket,
    ClientTicketRequest, EncryptedClientHello, EncryptedClientHelloOuter, PresharedKeyBinder,
    PresharedKeyIdentity, PresharedKeyOffer, PskKeyExchangeModes, ServerNamePayload,
};

mod codec;
pub(crate) use codec::{
    CERTIFICATE_MAX_SIZE_LIMIT, Codec, ListLength, MaybeEmpty, NonEmpty, Reader, SizedPayload,
    TlsListElement, hex, put_u16, put_u64,
};
use codec::{LengthPrefixedBuffer, U24};

mod deframer;
pub(crate) use deframer::{Deframed, Deframer, Delocator, HandshakeAlignedProof, Locator};

mod enums;
#[cfg(test)]
pub(crate) use enums::ECCurveType;
#[cfg(test)]
pub(crate) use enums::tests::{test_enum8, test_enum8_display, test_enum16};
pub(crate) use enums::{
    AlertLevel, AlertLevelName, ClientCertificateType, Compression, ExtensionType, KeyUpdateRequest,
};

mod fragmenter;
pub(crate) use fragmenter::{MAX_FRAGMENT_LEN, MessageFragmenter};

#[macro_use]
mod handshake;
use handshake::HELLO_RETRY_REQUEST_RANDOM;
pub(crate) use handshake::{
    ALL_KEY_EXCHANGE_ALGORITHMS, CertificateChain, CertificatePayloadTls13,
    CertificateRequestExtensions, CertificateRequestPayload, CertificateRequestPayloadTls13,
    CertificateStatus, ClientDhParams, ClientEcdhParams, ClientExtensionsInput,
    ClientKeyExchangeParams, CompressedCertificatePayload, Encoding, HelloRetryRequest,
    HelloRetryRequestExtensions, KeyShareEntry, KxDecode, NewSessionTicketPayload,
    NewSessionTicketPayloadTls13, Random, ServerExtensionsInput, ServerKeyExchange,
    ServerKeyExchangeParams, ServerKeyExchangePayload, SessionId, SingleProtocolName,
    SupportedEcPointFormats, SupportedProtocolVersions, TransportParameters,
};
#[cfg(test)]
pub(crate) use handshake::{EcParameters, NewSessionTicketExtensions, ServerEcdhParams};

mod server_hello;
pub(crate) use server_hello::{
    EchConfigContents, EchConfigPayload, HpkeKeyConfig, ServerExtensions, ServerHelloPayload,
    ServerTicketRequestHint,
};

#[cfg(test)]
mod handshake_test;

pub mod fuzzing {
    pub use super::deframer::fuzz_deframer;
    use super::{Codec, EncodedMessage, Message, MessageFragmenter, Payload, Reader};
    use crate::server::ServerSessionValue;

    pub fn fuzz_fragmenter(data: &[u8]) {
        let mut rdr = Reader::new(data);
        let Ok(msg) = EncodedMessage::<Payload<'_>>::read(&mut rdr) else {
            return;
        };

        let Ok(msg) = Message::try_from(&msg) else {
            return;
        };

        let mut frg = MessageFragmenter::default();
        frg.set_max_fragment_size(Some(32))
            .unwrap();
        for msg in frg.fragment_message(&EncodedMessage::<Payload<'_>>::from(msg)) {
            Message::try_from(&EncodedMessage {
                typ: msg.typ,
                version: msg.version,
                payload: Payload::Owned(msg.payload.to_vec()),
            })
            .ok();
        }
    }

    pub fn fuzz_message(data: &[u8]) {
        let mut rdr = Reader::new(data);
        let Ok(m) = EncodedMessage::<Payload<'_>>::read(&mut rdr) else {
            return;
        };

        let Ok(msg) = Message::try_from(&m) else {
            return;
        };

        //println!("msg = {:#?}", m);
        let enc = EncodedMessage::<Payload<'_>>::from(msg)
            .borrow_outbound()
            .to_unencrypted_bytes();
        //println!("data = {:?}", &data[..rdr.used()]);
        assert_eq!(enc, data[..data.len() - rdr.left()]);
    }

    pub fn fuzz_server_session_value(data: &[u8]) {
        let mut rdr = Reader::new(data);
        let _ = ServerSessionValue::read(&mut rdr);
    }
}

/// A message with decoded payload
#[derive(Debug)]
pub(crate) struct Message<'a> {
    pub version: ProtocolVersion,
    pub payload: MessagePayload<'a>,
}

impl Message<'_> {
    pub(crate) fn build_alert(level: AlertLevel, desc: AlertDescription) -> Self {
        Self {
            version: ProtocolVersion::TLSv1_2,
            payload: MessagePayload::Alert(AlertMessagePayload {
                level,
                description: desc,
            }),
        }
    }

    pub(crate) fn build_key_update_notify() -> Self {
        Self {
            version: ProtocolVersion::TLSv1_3,
            payload: MessagePayload::handshake(HandshakeMessagePayload(
                HandshakePayload::KeyUpdate(KeyUpdateRequest::UpdateNotRequested),
            )),
        }
    }

    pub(crate) fn build_key_update_request() -> Self {
        Self {
            version: ProtocolVersion::TLSv1_3,
            payload: MessagePayload::handshake(HandshakeMessagePayload(
                HandshakePayload::KeyUpdate(KeyUpdateRequest::UpdateRequested),
            )),
        }
    }

    pub(crate) fn into_owned(self) -> Message<'static> {
        let Self { version, payload } = self;
        Message {
            version,
            payload: payload.into_owned(),
        }
    }

    #[cfg(test)]
    pub(crate) fn into_wire_bytes(self) -> Vec<u8> {
        EncodedMessage::<Payload<'_>>::from(self)
            .borrow_outbound()
            .to_unencrypted_bytes()
    }

    pub(crate) fn handshake_type(&self) -> Option<HandshakeType> {
        match &self.payload {
            MessagePayload::Handshake { parsed, .. } => Some(parsed.0.handshake_type()),
            _ => None,
        }
    }
}

impl<'a> TryFrom<EncodedMessage<&'a [u8]>> for Message<'a> {
    type Error = InvalidMessage;

    fn try_from(plain: EncodedMessage<&'a [u8]>) -> Result<Self, Self::Error> {
        Ok(Self {
            version: plain.version,
            payload: MessagePayload::new(plain.typ, plain.version, plain.payload)?,
        })
    }
}

impl<'a> TryFrom<&'a EncodedMessage<Payload<'a>>> for Message<'a> {
    type Error = InvalidMessage;

    fn try_from(plain: &'a EncodedMessage<Payload<'a>>) -> Result<Self, Self::Error> {
        Ok(Self {
            version: plain.version,
            payload: MessagePayload::new(plain.typ, plain.version, plain.payload.bytes())?,
        })
    }
}

pub(crate) fn read_opaque_message_header(
    r: &mut Reader<'_>,
) -> Result<(ContentType, ProtocolVersion, u16), MessageError> {
    let typ = ContentType::read(r).map_err(|_| MessageError::TooShortForHeader)?;
    // Don't accept any new content-types.
    if ContentTypeName::try_from(typ).is_err() {
        return Err(MessageError::InvalidContentType);
    }

    let version = ProtocolVersion::read(r).map_err(|_| MessageError::TooShortForHeader)?;
    // Accept only versions 0x03XX for any XX.
    if version.0 & 0xff00 != 0x0300 {
        return Err(MessageError::UnknownProtocolVersion);
    }

    let len = u16::read(r).map_err(|_| MessageError::TooShortForHeader)?;

    // Reject undersize messages
    //  implemented per section 5.1 of RFC8446 (TLSv1.3)
    //              per section 6.2.1 of RFC5246 (TLSv1.2)
    if typ != ContentType::ApplicationData && len == 0 {
        return Err(MessageError::InvalidEmptyPayload);
    }

    // Reject oversize messages
    if len >= MAX_PAYLOAD {
        return Err(MessageError::MessageTooLarge);
    }

    Ok((typ, version, len))
}

#[non_exhaustive]
#[derive(Debug)]
pub(crate) enum MessagePayload<'a> {
    Alert(AlertMessagePayload),
    // one handshake message, parsed
    Handshake {
        parsed: HandshakeMessagePayload<'a>,
        encoded: Payload<'a>,
    },
    // (potentially) multiple handshake messages, unparsed
    HandshakeFlight(Payload<'a>),
    ChangeCipherSpec(ChangeCipherSpecPayload),
    ApplicationData(Payload<'a>),
}

impl<'a> MessagePayload<'a> {
    pub(crate) fn encode(&self, bytes: &mut Vec<u8>) {
        match self {
            Self::Alert(x) => x.encode(bytes),
            Self::Handshake { encoded, .. } => bytes.extend(encoded.bytes()),
            Self::HandshakeFlight(x) => bytes.extend(x.bytes()),
            Self::ChangeCipherSpec(x) => x.encode(bytes),
            Self::ApplicationData(x) => x.encode(bytes),
        }
    }

    pub(crate) fn handshake(parsed: HandshakeMessagePayload<'a>) -> Self {
        Self::Handshake {
            encoded: Payload::new(parsed.get_encoding()),
            parsed,
        }
    }

    pub(crate) fn new(
        typ: ContentType,
        vers: ProtocolVersion,
        payload: &'a [u8],
    ) -> Result<Self, InvalidMessage> {
        let mut r = Reader::new(payload);
        match typ {
            ContentType::ApplicationData => Ok(Self::ApplicationData(Payload::Borrowed(payload))),
            ContentType::Alert => AlertMessagePayload::read(&mut r).map(MessagePayload::Alert),
            ContentType::Handshake => {
                HandshakeMessagePayload::read_version(&mut r, vers).map(|parsed| Self::Handshake {
                    parsed,
                    encoded: Payload::Borrowed(payload),
                })
            }
            ContentType::ChangeCipherSpec => {
                ChangeCipherSpecPayload::read(&mut r).map(MessagePayload::ChangeCipherSpec)
            }
            _ => Err(InvalidMessage::InvalidContentType),
        }
    }

    pub(crate) fn content_type(&self) -> ContentType {
        match self {
            Self::Alert(_) => ContentType::Alert,
            Self::Handshake { .. } | Self::HandshakeFlight(_) => ContentType::Handshake,
            Self::ChangeCipherSpec(_) => ContentType::ChangeCipherSpec,
            Self::ApplicationData(_) => ContentType::ApplicationData,
        }
    }

    pub(crate) fn into_owned(self) -> MessagePayload<'static> {
        use MessagePayload::*;
        match self {
            Alert(x) => Alert(x),
            Handshake { parsed, encoded } => Handshake {
                parsed: parsed.into_owned(),
                encoded: encoded.into_owned(),
            },
            HandshakeFlight(x) => HandshakeFlight(x.into_owned()),
            ChangeCipherSpec(x) => ChangeCipherSpec(x),
            ApplicationData(x) => ApplicationData(x.into_owned()),
        }
    }
}

impl From<Message<'_>> for EncodedMessage<Payload<'_>> {
    fn from(msg: Message<'_>) -> Self {
        let typ = msg.payload.content_type();
        let payload = match msg.payload {
            MessagePayload::ApplicationData(payload) => payload.into_owned(),
            _ => {
                let mut buf = Vec::new();
                msg.payload.encode(&mut buf);
                Payload::Owned(buf)
            }
        };

        Self {
            typ,
            version: msg.version,
            payload,
        }
    }
}

#[derive(Debug)]
pub(crate) struct HandshakeMessagePayload<'a>(pub(crate) HandshakePayload<'a>);

impl<'a> Codec<'a> for HandshakeMessagePayload<'a> {
    fn encode(&self, bytes: &mut Vec<u8>) {
        self.payload_encode(bytes, Encoding::Standard);
    }

    fn read(r: &mut Reader<'a>) -> Result<Self, InvalidMessage> {
        Self::read_version(r, ProtocolVersion::TLSv1_2)
    }
}

impl<'a> HandshakeMessagePayload<'a> {
    pub(crate) fn read_version(
        r: &mut Reader<'a>,
        vers: ProtocolVersion,
    ) -> Result<Self, InvalidMessage> {
        let typ = HandshakeType::read(r)?;
        let len = U24::read(r)?.0 as usize;
        r.sub(len)?
            .all("HandshakeMessagePayload", |sub| {
                Ok(Self(match typ {
                    HandshakeType::HelloRequest if sub.left() == 0 => {
                        HandshakePayload::HelloRequest
                    }
                    HandshakeType::ClientHello => {
                        HandshakePayload::ClientHello(ClientHelloPayload::read(sub)?)
                    }
                    HandshakeType::ServerHello => {
                        let version = ProtocolVersion::read(sub)?;
                        let random = Random::read(sub)?;

                        if random == HELLO_RETRY_REQUEST_RANDOM {
                            let mut hrr = HelloRetryRequest::read(sub)?;
                            hrr.legacy_version = version;
                            HandshakePayload::HelloRetryRequest(hrr)
                        } else {
                            let mut shp = ServerHelloPayload::read(sub)?;
                            shp.legacy_version = version;
                            shp.random = random;
                            HandshakePayload::ServerHello(shp)
                        }
                    }
                    HandshakeType::Certificate if vers == ProtocolVersion::TLSv1_3 => {
                        let p = CertificatePayloadTls13::read(sub)?;
                        HandshakePayload::CertificateTls13(p)
                    }
                    HandshakeType::Certificate => {
                        HandshakePayload::Certificate(CertificateChain::read(sub)?)
                    }
                    HandshakeType::ServerKeyExchange => {
                        let p = ServerKeyExchangePayload::read(sub)?;
                        HandshakePayload::ServerKeyExchange(p)
                    }
                    HandshakeType::ServerHelloDone => HandshakePayload::ServerHelloDone,
                    HandshakeType::ClientKeyExchange => {
                        HandshakePayload::ClientKeyExchange(Payload::read(sub))
                    }
                    HandshakeType::CertificateRequest if vers == ProtocolVersion::TLSv1_3 => {
                        let p = CertificateRequestPayloadTls13::read(sub)?;
                        HandshakePayload::CertificateRequestTls13(p)
                    }
                    HandshakeType::CertificateRequest => {
                        let p = CertificateRequestPayload::read(sub)?;
                        HandshakePayload::CertificateRequest(p)
                    }
                    HandshakeType::CompressedCertificate => {
                        HandshakePayload::CompressedCertificate(CompressedCertificatePayload::read(
                            sub,
                        )?)
                    }
                    HandshakeType::CertificateVerify => {
                        HandshakePayload::CertificateVerify(DigitallySignedStruct::read(sub)?)
                    }
                    HandshakeType::NewSessionTicket if vers == ProtocolVersion::TLSv1_3 => {
                        let p = NewSessionTicketPayloadTls13::read(sub)?;
                        HandshakePayload::NewSessionTicketTls13(p)
                    }
                    HandshakeType::NewSessionTicket => {
                        let p = NewSessionTicketPayload::read(sub)?;
                        HandshakePayload::NewSessionTicket(p)
                    }
                    HandshakeType::EncryptedExtensions => HandshakePayload::EncryptedExtensions(
                        Box::new(ServerExtensions::read(sub)?),
                    ),
                    HandshakeType::KeyUpdate => {
                        HandshakePayload::KeyUpdate(KeyUpdateRequest::read(sub)?)
                    }
                    HandshakeType::EndOfEarlyData => HandshakePayload::EndOfEarlyData,
                    HandshakeType::Finished => HandshakePayload::Finished(Payload::read(sub)),
                    HandshakeType::CertificateStatus => {
                        HandshakePayload::CertificateStatus(CertificateStatus::read(sub)?)
                    }
                    HandshakeType::MessageHash => {
                        // does not appear on the wire
                        return Err(InvalidMessage::UnexpectedMessage("MessageHash"));
                    }
                    HandshakeType::HelloRetryRequest => {
                        // not legal on wire
                        return Err(InvalidMessage::UnexpectedMessage("HelloRetryRequest"));
                    }
                    _ => HandshakePayload::Unknown((typ, Payload::read(sub))),
                }))
            })
    }

    pub(crate) fn encoding_for_binder_signing(&self) -> Vec<u8> {
        let mut ret = self.get_encoding();
        let ret_len = ret.len() - self.total_binder_length();
        ret.truncate(ret_len);
        ret
    }

    pub(crate) fn total_binder_length(&self) -> usize {
        match &self.0 {
            HandshakePayload::ClientHello(ch) => match &ch.preshared_key_offer {
                Some(offer) => {
                    let mut binders_encoding = Vec::new();
                    offer
                        .binders
                        .encode(&mut binders_encoding);
                    binders_encoding.len()
                }
                _ => 0,
            },
            _ => 0,
        }
    }

    pub(crate) fn payload_encode(&self, bytes: &mut Vec<u8>, encoding: Encoding) {
        // output type, length, and encoded payload
        self.0
            .wire_handshake_type()
            .encode(bytes);

        let nested = LengthPrefixedBuffer::new(
            ListLength::U24 {
                max: usize::MAX,
                error: InvalidMessage::MessageTooLarge,
            },
            bytes,
        );

        match &self.0 {
            // for Server Hello and HelloRetryRequest payloads we need to encode the payload
            // differently based on the purpose of the encoding.
            HandshakePayload::ServerHello(payload) => payload.payload_encode(nested.buf, encoding),
            HandshakePayload::HelloRetryRequest(payload) => {
                payload.payload_encode(nested.buf, encoding)
            }

            // All other payload types are encoded the same regardless of purpose.
            _ => self.0.encode(nested.buf),
        }
    }

    pub(crate) fn build_handshake_hash(hash: &[u8]) -> Self {
        Self(HandshakePayload::MessageHash(Payload::new(hash.to_vec())))
    }

    pub(crate) fn into_owned(self) -> HandshakeMessagePayload<'static> {
        HandshakeMessagePayload(self.0.into_owned())
    }
}

#[derive(Debug)]
pub(crate) enum HandshakePayload<'a> {
    HelloRequest,
    ClientHello(ClientHelloPayload),
    ServerHello(ServerHelloPayload),
    HelloRetryRequest(HelloRetryRequest),
    Certificate(CertificateChain<'a>),
    CertificateTls13(CertificatePayloadTls13<'a>),
    CompressedCertificate(CompressedCertificatePayload<'a>),
    ServerKeyExchange(ServerKeyExchangePayload),
    CertificateRequest(CertificateRequestPayload),
    CertificateRequestTls13(CertificateRequestPayloadTls13),
    CertificateVerify(DigitallySignedStruct),
    ServerHelloDone,
    EndOfEarlyData,
    ClientKeyExchange(Payload<'a>),
    NewSessionTicket(NewSessionTicketPayload),
    NewSessionTicketTls13(NewSessionTicketPayloadTls13),
    EncryptedExtensions(Box<ServerExtensions<'a>>),
    KeyUpdate(KeyUpdateRequest),
    Finished(Payload<'a>),
    CertificateStatus(CertificateStatus<'a>),
    MessageHash(Payload<'a>),
    Unknown((HandshakeType, Payload<'a>)),
}

impl HandshakePayload<'_> {
    fn encode(&self, bytes: &mut Vec<u8>) {
        use self::HandshakePayload::*;
        match self {
            HelloRequest | ServerHelloDone | EndOfEarlyData => {}
            ClientHello(x) => x.encode(bytes),
            ServerHello(x) => x.encode(bytes),
            HelloRetryRequest(x) => x.encode(bytes),
            Certificate(x) => x.encode(bytes),
            CertificateTls13(x) => x.encode(bytes),
            CompressedCertificate(x) => x.encode(bytes),
            ServerKeyExchange(x) => x.encode(bytes),
            ClientKeyExchange(x) => x.encode(bytes),
            CertificateRequest(x) => x.encode(bytes),
            CertificateRequestTls13(x) => x.encode(bytes),
            CertificateVerify(x) => x.encode(bytes),
            NewSessionTicket(x) => x.encode(bytes),
            NewSessionTicketTls13(x) => x.encode(bytes),
            EncryptedExtensions(x) => x.encode(bytes),
            KeyUpdate(x) => x.encode(bytes),
            Finished(x) => x.encode(bytes),
            CertificateStatus(x) => x.encode(bytes),
            MessageHash(x) => x.encode(bytes),
            Unknown((_, x)) => x.encode(bytes),
        }
    }

    pub(crate) fn handshake_type(&self) -> HandshakeType {
        use self::HandshakePayload::*;
        match self {
            HelloRequest => HandshakeType::HelloRequest,
            ClientHello(_) => HandshakeType::ClientHello,
            ServerHello(_) => HandshakeType::ServerHello,
            HelloRetryRequest(_) => HandshakeType::HelloRetryRequest,
            Certificate(_) | CertificateTls13(_) => HandshakeType::Certificate,
            CompressedCertificate(_) => HandshakeType::CompressedCertificate,
            ServerKeyExchange(_) => HandshakeType::ServerKeyExchange,
            CertificateRequest(_) | CertificateRequestTls13(_) => HandshakeType::CertificateRequest,
            CertificateVerify(_) => HandshakeType::CertificateVerify,
            ServerHelloDone => HandshakeType::ServerHelloDone,
            EndOfEarlyData => HandshakeType::EndOfEarlyData,
            ClientKeyExchange(_) => HandshakeType::ClientKeyExchange,
            NewSessionTicket(_) | NewSessionTicketTls13(_) => HandshakeType::NewSessionTicket,
            EncryptedExtensions(_) => HandshakeType::EncryptedExtensions,
            KeyUpdate(_) => HandshakeType::KeyUpdate,
            Finished(_) => HandshakeType::Finished,
            CertificateStatus(_) => HandshakeType::CertificateStatus,
            MessageHash(_) => HandshakeType::MessageHash,
            Unknown((t, _)) => *t,
        }
    }

    fn wire_handshake_type(&self) -> HandshakeType {
        match self.handshake_type() {
            // A `HelloRetryRequest` appears on the wire as a `ServerHello` with a magic `random` value.
            HandshakeType::HelloRetryRequest => HandshakeType::ServerHello,
            other => other,
        }
    }

    fn into_owned(self) -> HandshakePayload<'static> {
        use HandshakePayload::*;

        match self {
            HelloRequest => HelloRequest,
            ClientHello(x) => ClientHello(x),
            ServerHello(x) => ServerHello(x),
            HelloRetryRequest(x) => HelloRetryRequest(x),
            Certificate(x) => Certificate(x.into_owned()),
            CertificateTls13(x) => CertificateTls13(x.into_owned()),
            CompressedCertificate(x) => CompressedCertificate(x.into_owned()),
            ServerKeyExchange(x) => ServerKeyExchange(x),
            CertificateRequest(x) => CertificateRequest(x),
            CertificateRequestTls13(x) => CertificateRequestTls13(x),
            CertificateVerify(x) => CertificateVerify(x),
            ServerHelloDone => ServerHelloDone,
            EndOfEarlyData => EndOfEarlyData,
            ClientKeyExchange(x) => ClientKeyExchange(x.into_owned()),
            NewSessionTicket(x) => NewSessionTicket(x),
            NewSessionTicketTls13(x) => NewSessionTicketTls13(x),
            EncryptedExtensions(x) => EncryptedExtensions(Box::new(x.into_owned())),
            KeyUpdate(x) => KeyUpdate(x),
            Finished(x) => Finished(x.into_owned()),
            CertificateStatus(x) => CertificateStatus(x.into_owned()),
            MessageHash(x) => MessageHash(x.into_owned()),
            Unknown((t, x)) => Unknown((t, x.into_owned())),
        }
    }
}

#[derive(Debug)]
pub(crate) struct AlertMessagePayload {
    pub level: AlertLevel,
    pub description: AlertDescription,
}

impl Codec<'_> for AlertMessagePayload {
    fn encode(&self, bytes: &mut Vec<u8>) {
        self.level.encode(bytes);
        self.description.encode(bytes);
    }

    fn read(r: &mut Reader<'_>) -> Result<Self, InvalidMessage> {
        r.all("AlertMessagePayload", |r| {
            Ok(Self {
                level: AlertLevel::read(r)?,
                description: AlertDescription::read(r)?,
            })
        })
    }
}

#[derive(Debug)]
pub(crate) struct ChangeCipherSpecPayload;

impl Codec<'_> for ChangeCipherSpecPayload {
    fn encode(&self, bytes: &mut Vec<u8>) {
        1u8.encode(bytes);
    }

    fn read(r: &mut Reader<'_>) -> Result<Self, InvalidMessage> {
        r.all("ChangeCipherSpecPayload", |r| {
            let typ = u8::read(r)?;
            if typ != 1 {
                return Err(InvalidMessage::InvalidCcs);
            }
            Ok(Self)
        })
    }
}

/// Content type, version and size.
pub(crate) const HEADER_SIZE: usize = 1 + 2 + 2;

/// Maximum message payload size.
/// That's 2^14 payload bytes and a 2KB allowance for ciphertext overheads.
pub(crate) const MAX_PAYLOAD: u16 = 16_384 + 2048;

#[cfg(test)]
mod tests {
    use alloc::vec;
    use std::io::Read;
    use std::path::{Path, PathBuf};
    use std::{format, fs, println};

    use super::*;
    use crate::error::AlertDescription;

    #[test]
    fn test_read_fuzz_corpus() {
        fn corpus_dir() -> PathBuf {
            let from_subcrate = Path::new("../fuzz/corpus/message");
            let from_root = Path::new("fuzz/corpus/message");

            if from_root.is_dir() {
                from_root.to_path_buf()
            } else {
                from_subcrate.to_path_buf()
            }
        }

        for file in fs::read_dir(corpus_dir()).unwrap() {
            let mut f = fs::File::open(file.unwrap().path()).unwrap();
            let mut bytes = Vec::new();
            f.read_to_end(&mut bytes).unwrap();

            let mut rd = Reader::new(&bytes);
            let msg = EncodedMessage::<Payload<'_>>::read(&mut rd).unwrap();
            println!("{msg:?}");

            let Ok(msg) = Message::try_from(&msg) else {
                continue;
            };

            let enc = EncodedMessage::<Payload<'_>>::from(msg)
                .borrow_outbound()
                .to_unencrypted_bytes();
            assert_eq!(bytes.to_vec(), enc);
            assert_eq!(bytes[..bytes.len() - rd.left()].to_vec(), enc);
        }
    }

    #[test]
    fn can_read_safari_client_hello_with_ip_address_in_sni_extension() {
        let _ = env_logger::Builder::new()
            .filter(None, log::LevelFilter::Trace)
            .try_init();

        let bytes = b"\
        \x16\x03\x01\x00\xeb\x01\x00\x00\xe7\x03\x03\xb6\x1f\xe4\x3a\x55\
        \x90\x3e\xc0\x28\x9c\x12\xe0\x5c\x84\xea\x90\x1b\xfb\x11\xfc\xbd\
        \x25\x55\xda\x9f\x51\x93\x1b\x8d\x92\x66\xfd\x00\x00\x2e\xc0\x2c\
        \xc0\x2b\xc0\x24\xc0\x23\xc0\x0a\xc0\x09\xcc\xa9\xc0\x30\xc0\x2f\
        \xc0\x28\xc0\x27\xc0\x14\xc0\x13\xcc\xa8\x00\x9d\x00\x9c\x00\x3d\
        \x00\x3c\x00\x35\x00\x2f\xc0\x08\xc0\x12\x00\x0a\x01\x00\x00\x90\
        \xff\x01\x00\x01\x00\x00\x00\x00\x0e\x00\x0c\x00\x00\x09\x31\x32\
        \x37\x2e\x30\x2e\x30\x2e\x31\x00\x17\x00\x00\x00\x0d\x00\x18\x00\
        \x16\x04\x03\x08\x04\x04\x01\x05\x03\x02\x03\x08\x05\x08\x05\x05\
        \x01\x08\x06\x06\x01\x02\x01\x00\x05\x00\x05\x01\x00\x00\x00\x00\
        \x33\x74\x00\x00\x00\x12\x00\x00\x00\x10\x00\x30\x00\x2e\x02\x68\
        \x32\x05\x68\x32\x2d\x31\x36\x05\x68\x32\x2d\x31\x35\x05\x68\x32\
        \x2d\x31\x34\x08\x73\x70\x64\x79\x2f\x33\x2e\x31\x06\x73\x70\x64\
        \x79\x2f\x33\x08\x68\x74\x74\x70\x2f\x31\x2e\x31\x00\x0b\x00\x02\
        \x01\x00\x00\x0a\x00\x0a\x00\x08\x00\x1d\x00\x17\x00\x18\x00\x19";
        let mut rd = Reader::new(bytes);
        let m = EncodedMessage::<Payload<'_>>::read(&mut rd).unwrap();
        println!("m = {m:?}");
        Message::try_from(&m).unwrap();
    }

    #[test]
    fn alert_is_not_handshake() {
        let m = Message::build_alert(AlertLevel::Fatal, AlertDescription::DecodeError);
        assert_ne!(m.handshake_type(), Some(HandshakeType::ClientHello));
    }

    #[test]
    fn construct_all_types() {
        let samples = [
            &b"\x14\x03\x04\x00\x01\x01"[..],
            &b"\x15\x03\x04\x00\x02\x01\x16"[..],
            &b"\x16\x03\x04\x00\x05\x18\x00\x00\x01\x00"[..],
            &b"\x17\x03\x04\x00\x04\x11\x22\x33\x44"[..],
            &b"\x18\x03\x04\x00\x04\x11\x22\x33\x44"[..],
        ];
        for &bytes in samples.iter() {
            let m = EncodedMessage::<Payload<'_>>::read(&mut Reader::new(bytes)).unwrap();
            println!("m = {m:?}");
            let m = Message::try_from(&m);
            println!("m' = {m:?}");
        }
    }

    #[test]
    fn debug_payload() {
        assert_eq!("01020304", format!("{:?}", Payload::new(vec![1, 2, 3, 4])));
        assert_eq!(
            "01020304",
            format!("{:?}", SizedPayload::<u8, NonEmpty>::from(vec![1, 2, 3, 4]))
        );
        assert_eq!(
            "01020304",
            format!(
                "{:?}",
                SizedPayload::<u16, MaybeEmpty>::from(vec![1, 2, 3, 4])
            )
        );
        assert_eq!(
            "01020304",
            format!(
                "{:?}",
                SizedPayload::<'static, U24, NonEmpty>::from(Payload::new(vec![1, 2, 3, 4]))
            )
        );
    }

    #[test]
    fn into_wire_format() {
        // Message::into_wire_bytes() include both message-level and handshake-level headers
        assert_eq!(
            Message::build_key_update_request().into_wire_bytes(),
            &[0x16, 0x3, 0x4, 0x0, 0x5, 0x18, 0x0, 0x0, 0x1, 0x1]
        );
    }

    #[test]
    fn smoketest() {
        let bytes = include_bytes!("../testdata/handshake-test.1.bin");
        let mut r = Reader::new(bytes);

        while r.any_left() {
            let m = EncodedMessage::<Payload<'_>>::read(&mut r).unwrap();

            let out = m
                .borrow_outbound()
                .to_unencrypted_bytes();
            assert!(!out.is_empty());

            Message::try_from(&m).unwrap();
        }
    }
}