tls.rs

//! # TLS parser
//! Parsing functions for the TLS protocol, supporting versions 1.0 to 1.3

use alloc::{vec, vec::Vec};
use core::convert::{AsRef, TryInto};
use core::fmt;
use core::ops::Deref;
use nom::branch::alt;
use nom::bytes::streaming::take;
use nom::combinator::{complete, cond, map, map_parser, opt, verify};
use nom::error::{make_error, ErrorKind};
use nom::multi::{length_count, length_data, many0, many1};
use nom::number::streaming::{be_u16, be_u24, be_u32, be_u8};
use nom_derive::*;
use rusticata_macros::newtype_enum;
use serde::Serialize;

use crate::tls_alert::*;
use crate::tls_ciphers::*;

pub use nom::{Err, IResult};

/// Max record size (RFC8446 5.1)
pub const MAX_RECORD_LEN: u16 = 1 << 14;

/// Handshake type
///
/// Handshake types are defined in [RFC5246](https://tools.ietf.org/html/rfc5246) and
/// the [IANA HandshakeType
/// Registry](https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-7)
#[derive(Clone, Copy, PartialEq, Eq, NomBE, Hash)]
pub struct TlsHandshakeType(pub u8);

newtype_enum! {
impl debug TlsHandshakeType {
    HelloRequest        = 0x00,
    ClientHello         = 0x01,
    ServerHello         = 0x02,
    HelloVerifyRequest  = 0x03,
    NewSessionTicket    = 0x04,
    EndOfEarlyData      = 0x05,
    HelloRetryRequest   = 0x06,
    EncryptedExtensions = 0x08,
    Certificate         = 0x0b,
    ServerKeyExchange   = 0x0c,
    CertificateRequest  = 0x0d,
    ServerDone          = 0x0e,
    CertificateVerify   = 0x0f,
    ClientKeyExchange   = 0x10,
    Finished            = 0x14,
    CertificateURL      = 0x15,
    CertificateStatus   = 0x16,
    KeyUpdate           = 0x18,

    NextProtocol        = 0x43,
}
}

impl From<TlsHandshakeType> for u8 {
    fn from(v: TlsHandshakeType) -> u8 {
        v.0
    }
}

/// TLS version
///
/// Only the TLS version defined in the TLS message header is meaningful, the
/// version defined in the record should be ignored or set to TLS 1.0
#[derive(Clone, Copy, Default, PartialEq, Eq, NomBE, Hash, Serialize)]
pub struct TlsVersion(pub u16);

impl TlsVersion {
    pub const fn to_be_bytes(&self) -> [u8; 2] {
        self.0.to_be_bytes()
    }
}

newtype_enum! {
impl debug TlsVersion {
    Ssl30        = 0x0300,
    Tls10        = 0x0301,
    Tls11        = 0x0302,
    Tls12        = 0x0303,
    Tls13        = 0x0304,

    Tls13Draft18 = 0x7f12,
    Tls13Draft19 = 0x7f13,
    Tls13Draft20 = 0x7f14,
    Tls13Draft21 = 0x7f15,
    Tls13Draft22 = 0x7f16,
    Tls13Draft23 = 0x7f17,
    Tls13Draft24 = 0x7f18,
    Tls13Draft25 = 0x7f19,
    Tls13Draft26 = 0x7f1a,
    Tls13Draft27 = 0x7f1b,
    Tls13Draft28 = 0x7f1c,
    Tls13FbDraft23 = 0xfb17,
    Tls13FbDraft26 = 0xfb1a,

    DTls10       = 0xfeff,
    DTls11       = 0xfefe,
    DTls12       = 0xfefd,
}
}

impl From<TlsVersion> for u16 {
    fn from(v: TlsVersion) -> u16 {
        v.0
    }
}

impl fmt::LowerHex for TlsVersion {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{:x}", self.0)
    }
}

/// Heartbeat type, as defined in [RFC6520](https://tools.ietf.org/html/rfc6520) section 3
#[derive(Clone, Copy, PartialEq, Eq, NomBE, Hash)]
pub struct TlsHeartbeatMessageType(pub u8);

newtype_enum! {
impl debug TlsHeartbeatMessageType {
    HeartBeatRequest  = 0x1,
    HeartBeatResponse = 0x2,
}
}

impl From<TlsHeartbeatMessageType> for u8 {
    fn from(v: TlsHeartbeatMessageType) -> u8 {
        v.0
    }
}

/// Content type, as defined in IANA TLS ContentType registry
#[derive(Clone, Copy, PartialEq, Eq, NomBE, Hash)]
pub struct TlsRecordType(pub u8);

newtype_enum! {
impl debug TlsRecordType {
    ChangeCipherSpec = 0x14,
    Alert            = 0x15,
    Handshake        = 0x16,
    ApplicationData  = 0x17,
    Heartbeat        = 0x18,
}
}

impl From<TlsRecordType> for u8 {
    fn from(v: TlsRecordType) -> u8 {
        v.0
    }
}

#[derive(Clone, Copy, Default, PartialEq, Eq, NomBE, Hash, Serialize)]
pub struct TlsCompressionID(pub u8);

newtype_enum! {
impl debug TlsCompressionID {
    Null = 0x00,
    Deflate = 0x01,
}
}

impl From<TlsCompressionID> for u8 {
    fn from(c: TlsCompressionID) -> u8 {
        c.0
    }
}

impl Deref for TlsCompressionID {
    type Target = u8;
    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

impl AsRef<u8> for TlsCompressionID {
    fn as_ref(&self) -> &u8 {
        &self.0
    }
}

#[derive(Clone, Copy, Default, PartialEq, Eq, NomBE, Hash, Serialize)]
pub struct TlsCipherSuiteID(pub u16);

impl TlsCipherSuiteID {
    pub fn get_ciphersuite(self) -> Option<&'static TlsCipherSuite> {
        TlsCipherSuite::from_id(self.0)
    }
}

impl From<TlsCipherSuiteID> for u16 {
    fn from(c: TlsCipherSuiteID) -> u16 {
        c.0
    }
}

impl Deref for TlsCipherSuiteID {
    type Target = u16;
    fn deref(&self) -> &Self::Target {
        &self.0
    }
}

impl AsRef<u16> for TlsCipherSuiteID {
    fn as_ref(&self) -> &u16 {
        &self.0
    }
}

impl fmt::Display for TlsCipherSuiteID {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match TlsCipherSuite::from_id(self.0) {
            Some(c) => write!(f, "{}", c.name),
            None => write!(f, "UNKNOWN_CIPHER"),
        }
    }
}

impl fmt::Debug for TlsCipherSuiteID {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        match TlsCipherSuite::from_id(self.0) {
            Some(c) => write!(f, "0x{:04x}({})", self.0, c.name),
            None => write!(f, "0x{:04x}(Unknown cipher)", self.0),
        }
    }
}

impl fmt::LowerHex for TlsCipherSuiteID {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        write!(f, "{:x}", self.0)
    }
}

/// A trait that both TLS & DTLS satisfy
pub trait ClientHello<'a> {
    /// TLS version of message
    fn version(&self) -> TlsVersion;
    fn random(&self) -> &'a [u8];
    // Get the first part (4 bytes) of random
    fn rand_time(&self) -> u32 {
        self.random()
            .try_into()
            .map(u32::from_be_bytes)
            .unwrap_or(0)
    }
    // Get the second part (28 bytes) of random
    fn rand_bytes(&self) -> &'a [u8] {
        self.random().get(4..).unwrap_or(&[])
    }
    fn session_id(&self) -> Option<&'a [u8]>;
    /// A list of ciphers supported by client
    fn ciphers(&self) -> &Vec<TlsCipherSuiteID>;
    fn cipher_suites(&self) -> Vec<Option<&'static TlsCipherSuite>> {
        self.ciphers()
            .iter()
            .map(|&x| x.get_ciphersuite())
            .collect()
    }
    /// A list of compression methods supported by client
    fn comp(&self) -> &Vec<TlsCompressionID>;
    fn ext(&self) -> Option<&'a [u8]>;
}

/// TLS Client Hello (from TLS 1.0 to TLS 1.2)
///
/// Some fields are unparsed (for performance reasons), for ex to parse `ext`,
/// call the `parse_tls_extensions` function.
#[derive(Clone, PartialEq, Hash)]
pub struct TlsClientHelloContents<'a> {
    /// TLS version of message
    pub version: TlsVersion,
    pub random: &'a [u8],
    pub session_id: Option<&'a [u8]>,
    /// A list of ciphers supported by client
    pub ciphers: Vec<TlsCipherSuiteID>,
    /// A list of compression methods supported by client
    pub comp: Vec<TlsCompressionID>,

    pub ext: Option<&'a [u8]>,
}

impl<'a> TlsClientHelloContents<'a> {
    pub fn new(
        v: u16,
        random: &'a [u8],
        sid: Option<&'a [u8]>,
        c: Vec<TlsCipherSuiteID>,
        co: Vec<TlsCompressionID>,
        e: Option<&'a [u8]>,
    ) -> Self {
        TlsClientHelloContents {
            version: TlsVersion(v),
            random,
            session_id: sid,
            ciphers: c,
            comp: co,
            ext: e,
        }
    }

    pub fn get_version(&self) -> TlsVersion {
        self.version
    }

    pub fn get_ciphers(&self) -> Vec<Option<&'static TlsCipherSuite>> {
        self.ciphers.iter().map(|&x| x.get_ciphersuite()).collect()
    }
}

impl<'a> ClientHello<'a> for TlsClientHelloContents<'a> {
    fn version(&self) -> TlsVersion {
        self.version
    }

    fn random(&self) -> &'a [u8] {
        self.random
    }

    fn session_id(&self) -> Option<&'a [u8]> {
        self.session_id
    }

    fn ciphers(&self) -> &Vec<TlsCipherSuiteID> {
        &self.ciphers
    }

    fn comp(&self) -> &Vec<TlsCompressionID> {
        &self.comp
    }

    fn ext(&self) -> Option<&'a [u8]> {
        self.ext
    }
}

/// TLS Server Hello (from TLS 1.0 to TLS 1.2)
#[derive(Clone, PartialEq, Hash)]
pub struct TlsServerHelloContents<'a> {
    pub version: TlsVersion,
    pub random: &'a [u8],
    pub session_id: Option<&'a [u8]>,
    pub cipher: TlsCipherSuiteID,
    pub compression: TlsCompressionID,

    pub ext: Option<&'a [u8]>,
}

/// TLS Server Hello (TLS 1.3 draft 18)
#[derive(Clone, PartialEq, Hash)]
pub struct TlsServerHelloV13Draft18Contents<'a> {
    pub version: TlsVersion,
    pub random: &'a [u8],
    pub cipher: TlsCipherSuiteID,

    pub ext: Option<&'a [u8]>,
}

/// TLS Hello Retry Request (TLS 1.3)
#[derive(Clone, PartialEq, Hash)]
pub struct TlsHelloRetryRequestContents<'a> {
    pub version: TlsVersion,
    pub cipher: TlsCipherSuiteID,

    pub ext: Option<&'a [u8]>,
}

impl<'a> TlsServerHelloContents<'a> {
    pub fn new(
        v: u16,
        random: &'a [u8],
        sid: Option<&'a [u8]>,
        c: u16,
        co: u8,
        e: Option<&'a [u8]>,
    ) -> Self {
        TlsServerHelloContents {
            version: TlsVersion(v),
            random,
            session_id: sid,
            cipher: TlsCipherSuiteID(c),
            compression: TlsCompressionID(co),
            ext: e,
        }
    }

    pub fn get_version(&self) -> TlsVersion {
        self.version
    }

    pub fn get_cipher(&self) -> Option<&'static TlsCipherSuite> {
        self.cipher.get_ciphersuite()
    }
}

/// Session ticket, as defined in [RFC5077](https://tools.ietf.org/html/rfc5077)
#[derive(Clone, Debug, PartialEq, Hash)]
pub struct TlsNewSessionTicketContent<'a> {
    pub ticket_lifetime_hint: u32,
    pub ticket: &'a [u8],
}

/// A raw certificate, which should be a DER-encoded X.509 certificate.
///
/// See [RFC5280](https://tools.ietf.org/html/rfc5280) for X509v3 certificate format.
#[derive(Clone, PartialEq, Hash)]
pub struct RawCertificate<'a> {
    pub data: &'a [u8],
}

/// The certificate chain, usually composed of the certificate, and all
/// required certificate authorities.
#[derive(Clone, Debug, PartialEq, Hash)]
pub struct TlsCertificateContents<'a> {
    pub cert_chain: Vec<RawCertificate<'a>>,
}

/// Certificate request, as defined in [RFC5246](https://tools.ietf.org/html/rfc5246) section 7.4.4
///
/// Note: TLS 1.2 adds SignatureAndHashAlgorithm (chapter 7.4.4) but do not declare it in A.4.2
#[derive(Clone, Debug, PartialEq, Hash)]
pub struct TlsCertificateRequestContents<'a> {
    pub cert_types: Vec<u8>,
    pub sig_hash_algs: Option<Vec<u16>>,
    /// A list of DER-encoded distinguished names. See
    /// [X.501](http://www.itu.int/rec/T-REC-X.501/en)
    pub unparsed_ca: Vec<&'a [u8]>,
}

/// Server key exchange parameters
///
/// This is an opaque struct, since the content depends on the selected
/// key exchange method.
#[derive(Clone, PartialEq, Hash)]
pub struct TlsServerKeyExchangeContents<'a> {
    pub parameters: &'a [u8],
}

/// Client key exchange parameters
///
/// This is an opaque struct, since the content depends on the selected
/// key exchange method.
#[derive(Clone, PartialEq, Hash)]
pub struct TlsClientKeyExchangeContents<'a> {
    pub parameters: &'a [u8],
}

/// Certificate status response, as defined in [RFC6066](https://tools.ietf.org/html/rfc6066) section 8
#[derive(Clone, Debug, PartialEq, Hash)]
pub struct TlsCertificateStatusContents<'a> {
    pub status_type: u8,
    pub blob: &'a [u8],
}

/// Next protocol response, defined in
/// [draft-agl-tls-nextprotoneg-03](https://tools.ietf.org/html/draft-agl-tls-nextprotoneg-03)
#[derive(Clone, Debug, PartialEq, Hash)]
pub struct TlsNextProtocolContent<'a> {
    pub selected_protocol: &'a [u8],
    pub padding: &'a [u8],
}

/// Key update request (TLS 1.3)
#[derive(Copy, Clone, PartialEq, Hash, Eq)]
pub struct KeyUpdateRequest(pub u8);

newtype_enum! {
impl KeyUpdateRequest {
    NotRequested  = 0x0,
    Requested     = 0x1,
}
}

/// Generic handshake message
#[derive(Clone, Debug, PartialEq, Hash)]
pub enum TlsMessageHandshake<'a> {
    HelloRequest,
    ClientHello(TlsClientHelloContents<'a>),
    ServerHello(TlsServerHelloContents<'a>),
    ServerHelloV13Draft18(TlsServerHelloV13Draft18Contents<'a>),
    NewSessionTicket(TlsNewSessionTicketContent<'a>),
    EndOfEarlyData,
    HelloRetryRequest(TlsHelloRetryRequestContents<'a>),
    Certificate(TlsCertificateContents<'a>),
    ServerKeyExchange(TlsServerKeyExchangeContents<'a>),
    CertificateRequest(TlsCertificateRequestContents<'a>),
    ServerDone(&'a [u8]),
    CertificateVerify(&'a [u8]),
    ClientKeyExchange(TlsClientKeyExchangeContents<'a>),
    Finished(&'a [u8]),
    CertificateStatus(TlsCertificateStatusContents<'a>),
    NextProtocol(TlsNextProtocolContent<'a>),
    KeyUpdate(u8),
}

/// TLS application data
///
/// Since this message can only be sent after the handshake, data is
/// stored as opaque.
#[derive(Clone, Debug, PartialEq, Hash)]
pub struct TlsMessageApplicationData<'a> {
    pub blob: &'a [u8],
}

/// TLS heartbeat message, as defined in [RFC6520](https://tools.ietf.org/html/rfc6520)
///
/// Heartbeat messages should not be sent during handshake, but in practise
/// they can (and this caused heartbleed).
#[derive(Clone, Debug, PartialEq, Hash)]
pub struct TlsMessageHeartbeat<'a> {
    pub heartbeat_type: TlsHeartbeatMessageType,
    pub payload_len: u16,
    pub payload: &'a [u8],
}

/// TLS record header
#[derive(Clone, Copy, PartialEq, NomBE, Hash)]
pub struct TlsRecordHeader {
    pub record_type: TlsRecordType,
    pub version: TlsVersion,
    pub len: u16,
}

/// TLS plaintext message
///
/// Plaintext records can only be found during the handshake.
#[derive(Clone, Debug, PartialEq, Hash)]
pub enum TlsMessage<'a> {
    Handshake(TlsMessageHandshake<'a>),
    ChangeCipherSpec,
    Alert(TlsMessageAlert),
    ApplicationData(TlsMessageApplicationData<'a>),
    Heartbeat(TlsMessageHeartbeat<'a>),
}

/// TLS plaintext record
///
/// A TLS record can contain multiple messages (sharing the same record type).
/// Plaintext records can only be found during the handshake.
#[derive(Clone, Debug, PartialEq, Hash)]
pub struct TlsPlaintext<'a> {
    pub hdr: TlsRecordHeader,
    pub msg: Vec<TlsMessage<'a>>,
}

/// TLS encrypted data
///
/// This struct only contains an opaque pointer (data are encrypted).
#[derive(Clone, Debug, PartialEq, Hash)]
pub struct TlsEncryptedContent<'a> {
    pub blob: &'a [u8],
}

/// Encrypted TLS record (containing opaque data)
#[derive(Clone, Debug, PartialEq, Hash)]
pub struct TlsEncrypted<'a> {
    pub hdr: TlsRecordHeader,
    pub msg: TlsEncryptedContent<'a>,
}

/// Tls Record with raw (unparsed) data
///
/// Use `parse_tls_raw_record` to parse content
#[derive(Clone, Debug, PartialEq, Hash)]
pub struct TlsRawRecord<'a> {
    pub hdr: TlsRecordHeader,
    pub data: &'a [u8],
}

pub(crate) fn parse_cipher_suites(i: &[u8], len: usize) -> IResult<&[u8], Vec<TlsCipherSuiteID>> {
    if len == 0 {
        return Ok((i, Vec::new()));
    }
    if len % 2 == 1 || len > i.len() {
        return Err(Err::Error(make_error(i, ErrorKind::LengthValue)));
    }
    let v = (&i[..len])
        .chunks(2)
        .map(|chunk| TlsCipherSuiteID((chunk[0] as u16) << 8 | chunk[1] as u16))
        .collect();
    Ok((&i[len..], v))
}

pub(crate) fn parse_compressions_algs(
    i: &[u8],
    len: usize,
) -> IResult<&[u8], Vec<TlsCompressionID>> {
    if len == 0 {
        return Ok((i, Vec::new()));
    }
    if len > i.len() {
        return Err(Err::Error(make_error(i, ErrorKind::LengthValue)));
    }
    let v = (&i[..len]).iter().map(|&it| TlsCompressionID(it)).collect();
    Ok((&i[len..], v))
}

pub(crate) fn parse_tls_versions(i: &[u8]) -> IResult<&[u8], Vec<TlsVersion>> {
    let len = i.len();
    if len == 0 {
        return Ok((i, Vec::new()));
    }
    if len % 2 == 1 || len > i.len() {
        return Err(Err::Error(make_error(i, ErrorKind::LengthValue)));
    }
    let v = (&i[..len])
        .chunks(2)
        .map(|chunk| TlsVersion((chunk[0] as u16) << 8 | chunk[1] as u16))
        .collect();
    Ok((&i[len..], v))
}

fn parse_certs(i: &[u8]) -> IResult<&[u8], Vec<RawCertificate>> {
    many0(complete(map(length_data(be_u24), |data| RawCertificate {
        data,
    })))(i)
}

/// Read TLS record header
///
/// This function is used to get the record header.
/// After calling this function, caller can read the expected number of bytes and use
/// `parse_tls_record_with_header` to parse content.
#[inline]
pub fn parse_tls_record_header(i: &[u8]) -> IResult<&[u8], TlsRecordHeader> {
    TlsRecordHeader::parse(i)
}

#[allow(clippy::unnecessary_wraps)]
fn parse_tls_handshake_msg_hello_request(i: &[u8]) -> IResult<&[u8], TlsMessageHandshake> {
    Ok((i, TlsMessageHandshake::HelloRequest))
}

fn parse_tls_handshake_msg_client_hello(i: &[u8]) -> IResult<&[u8], TlsMessageHandshake> {
    let (i, version) = be_u16(i)?;
    let (i, random) = take(32usize)(i)?;
    let (i, sidlen) = verify(be_u8, |&n| n <= 32)(i)?;
    let (i, sid) = cond(sidlen > 0, take(sidlen as usize))(i)?;
    let (i, ciphers_len) = be_u16(i)?;
    let (i, ciphers) = parse_cipher_suites(i, ciphers_len as usize)?;
    let (i, comp_len) = be_u8(i)?;
    let (i, comp) = parse_compressions_algs(i, comp_len as usize)?;
    let (i, ext) = opt(complete(length_data(be_u16)))(i)?;
    let content = TlsClientHelloContents::new(version, random, sid, ciphers, comp, ext);
    Ok((i, TlsMessageHandshake::ClientHello(content)))
}

fn parse_tls_handshake_msg_server_hello_tlsv12(i: &[u8]) -> IResult<&[u8], TlsMessageHandshake> {
    map(
        parse_tls_server_hello_tlsv12,
        TlsMessageHandshake::ServerHello,
    )(i)
}

pub(crate) fn parse_tls_server_hello_tlsv12(i: &[u8]) -> IResult<&[u8], TlsServerHelloContents> {
    let (i, version) = be_u16(i)?;
    let (i, random) = take(32usize)(i)?;
    let (i, sidlen) = verify(be_u8, |&n| n <= 32)(i)?;
    let (i, sid) = cond(sidlen > 0, take(sidlen as usize))(i)?;
    let (i, cipher) = be_u16(i)?;
    let (i, comp) = be_u8(i)?;
    let (i, ext) = opt(complete(length_data(be_u16)))(i)?;
    let content = TlsServerHelloContents::new(version, random, sid, cipher, comp, ext);
    Ok((i, content))
}

fn parse_tls_handshake_msg_server_hello_tlsv13draft18(
    i: &[u8],
) -> IResult<&[u8], TlsMessageHandshake> {
    let (i, version) = TlsVersion::parse(i)?;
    let (i, random) = take(32usize)(i)?;
    let (i, cipher) = map(be_u16, TlsCipherSuiteID)(i)?;
    let (i, ext) = opt(complete(length_data(be_u16)))(i)?;
    let content = TlsServerHelloV13Draft18Contents {
        version,
        random,
        cipher,
        ext,
    };
    Ok((i, TlsMessageHandshake::ServerHelloV13Draft18(content)))
}

fn parse_tls_handshake_msg_server_hello(i: &[u8]) -> IResult<&[u8], TlsMessageHandshake> {
    let (_, version) = be_u16(i)?;
    match version {
        0x7f12 => parse_tls_handshake_msg_server_hello_tlsv13draft18(i),
        0x0303 => parse_tls_handshake_msg_server_hello_tlsv12(i),
        0x0302 => parse_tls_handshake_msg_server_hello_tlsv12(i),
        0x0301 => parse_tls_handshake_msg_server_hello_tlsv12(i),
        // 0x0300 => call!(parse_tls_handshake_msg_server_hello_sslv3(i),
        _ => Err(Err::Error(make_error(i, ErrorKind::Tag))),
    }
}

// RFC 5077   Stateless TLS Session Resumption
fn parse_tls_handshake_msg_newsessionticket(
    i: &[u8],
    len: usize,
) -> IResult<&[u8], TlsMessageHandshake> {
    if len < 4 {
        return Err(Err::Error(make_error(i, ErrorKind::Verify)));
    }
    let (i, ticket_lifetime_hint) = be_u32(i)?;
    let (i, ticket) = take(len - 4)(i)?;
    let content = TlsNewSessionTicketContent {
        ticket_lifetime_hint,
        ticket,
    };
    Ok((i, TlsMessageHandshake::NewSessionTicket(content)))
}

fn parse_tls_handshake_msg_hello_retry_request(i: &[u8]) -> IResult<&[u8], TlsMessageHandshake> {
    let (i, version) = TlsVersion::parse(i)?;
    let (i, cipher) = map(be_u16, TlsCipherSuiteID)(i)?;
    let (i, ext) = opt(complete(length_data(be_u16)))(i)?;
    let content = TlsHelloRetryRequestContents {
        version,
        cipher,
        ext,
    };
    Ok((i, TlsMessageHandshake::HelloRetryRequest(content)))
}

pub(crate) fn parse_tls_certificate(i: &[u8]) -> IResult<&[u8], TlsCertificateContents> {
    let (i, cert_len) = be_u24(i)?;
    let (i, cert_chain) = map_parser(take(cert_len as usize), parse_certs)(i)?;
    let content = TlsCertificateContents { cert_chain };
    Ok((i, content))
}

fn parse_tls_handshake_msg_certificate(i: &[u8]) -> IResult<&[u8], TlsMessageHandshake> {
    map(parse_tls_certificate, TlsMessageHandshake::Certificate)(i)
}

fn parse_tls_handshake_msg_serverkeyexchange(
    i: &[u8],
    len: usize,
) -> IResult<&[u8], TlsMessageHandshake> {
    map(take(len), |ext| {
        TlsMessageHandshake::ServerKeyExchange(TlsServerKeyExchangeContents { parameters: ext })
    })(i)
}

fn parse_tls_handshake_msg_serverdone(i: &[u8], len: usize) -> IResult<&[u8], TlsMessageHandshake> {
    map(take(len), TlsMessageHandshake::ServerDone)(i)
}

fn parse_tls_handshake_msg_certificateverify(
    i: &[u8],
    len: usize,
) -> IResult<&[u8], TlsMessageHandshake> {
    map(take(len), TlsMessageHandshake::CertificateVerify)(i)
}

fn parse_tls_handshake_msg_clientkeyexchange(
    i: &[u8],
    len: usize,
) -> IResult<&[u8], TlsMessageHandshake> {
    map(take(len), |ext| {
        TlsMessageHandshake::ClientKeyExchange(TlsClientKeyExchangeContents { parameters: ext })
    })(i)
}

fn parse_certrequest_nosigalg(i: &[u8]) -> IResult<&[u8], TlsMessageHandshake> {
    let (i, cert_types) = length_count(be_u8, be_u8)(i)?;
    let (i, ca_len) = be_u16(i)?;
    let (i, unparsed_ca) =
        map_parser(take(ca_len as usize), many0(complete(length_data(be_u16))))(i)?;
    let content = TlsCertificateRequestContents {
        cert_types,
        // sig_hash_algs: Some(sig_hash_algs),
        sig_hash_algs: None,
        unparsed_ca,
    };
    Ok((i, TlsMessageHandshake::CertificateRequest(content)))
}

fn parse_certrequest_full(i: &[u8]) -> IResult<&[u8], TlsMessageHandshake> {
    let (i, cert_types) = length_count(be_u8, be_u8)(i)?;
    let (i, sig_hash_algs_len) = be_u16(i)?;
    let (i, sig_hash_algs) =
        map_parser(take(sig_hash_algs_len as usize), many0(complete(be_u16)))(i)?;
    let (i, ca_len) = be_u16(i)?;
    let (i, unparsed_ca) =
        map_parser(take(ca_len as usize), many0(complete(length_data(be_u16))))(i)?;
    let content = TlsCertificateRequestContents {
        cert_types,
        sig_hash_algs: Some(sig_hash_algs),
        unparsed_ca,
    };
    Ok((i, TlsMessageHandshake::CertificateRequest(content)))
}

#[inline]
fn parse_tls_handshake_msg_certificaterequest(i: &[u8]) -> IResult<&[u8], TlsMessageHandshake> {
    alt((
        complete(parse_certrequest_full),
        complete(parse_certrequest_nosigalg),
    ))(i)
}

fn parse_tls_handshake_msg_finished(i: &[u8], len: usize) -> IResult<&[u8], TlsMessageHandshake> {
    map(take(len), TlsMessageHandshake::Finished)(i)
}

// Defined in [RFC6066]
// if status_type == 0, blob is a OCSPResponse, as defined in [RFC2560](https://tools.ietf.org/html/rfc2560)
// Note that the OCSPResponse object is DER-encoded.
fn parse_tls_handshake_msg_certificatestatus(i: &[u8]) -> IResult<&[u8], TlsMessageHandshake> {
    let (i, status_type) = be_u8(i)?;
    let (i, blob) = length_data(be_u24)(i)?;
    let content = TlsCertificateStatusContents { status_type, blob };
    Ok((i, TlsMessageHandshake::CertificateStatus(content)))
}

/// NextProtocol handshake message, as defined in
/// [draft-agl-tls-nextprotoneg-03](https://tools.ietf.org/html/draft-agl-tls-nextprotoneg-03)
/// Deprecated in favour of ALPN.
fn parse_tls_handshake_msg_next_protocol(i: &[u8]) -> IResult<&[u8], TlsMessageHandshake> {
    let (i, selected_protocol) = length_data(be_u8)(i)?;
    let (i, padding) = length_data(be_u8)(i)?;
    let next_proto = TlsNextProtocolContent {
        selected_protocol,
        padding,
    };
    Ok((i, TlsMessageHandshake::NextProtocol(next_proto)))
}

fn parse_tls_handshake_msg_key_update(i: &[u8]) -> IResult<&[u8], TlsMessageHandshake> {
    map(be_u8, TlsMessageHandshake::KeyUpdate)(i)
}

/// Parse a TLS handshake message
pub fn parse_tls_message_handshake(i: &[u8]) -> IResult<&[u8], TlsMessage> {
    let (i, ht) = be_u8(i)?;
    let (i, hl) = be_u24(i)?;
    let (i, raw_msg) = take(hl)(i)?;
    let (_, msg) = match TlsHandshakeType(ht) {
        TlsHandshakeType::HelloRequest => parse_tls_handshake_msg_hello_request(raw_msg),
        TlsHandshakeType::ClientHello => parse_tls_handshake_msg_client_hello(raw_msg),
        TlsHandshakeType::ServerHello => parse_tls_handshake_msg_server_hello(raw_msg),
        TlsHandshakeType::NewSessionTicket => {
            parse_tls_handshake_msg_newsessionticket(raw_msg, hl as usize)
        }
        TlsHandshakeType::EndOfEarlyData => Ok((raw_msg, TlsMessageHandshake::EndOfEarlyData)),
        TlsHandshakeType::HelloRetryRequest => parse_tls_handshake_msg_hello_retry_request(raw_msg),
        TlsHandshakeType::Certificate => parse_tls_handshake_msg_certificate(raw_msg),
        TlsHandshakeType::ServerKeyExchange => {
            parse_tls_handshake_msg_serverkeyexchange(raw_msg, hl as usize)
        }
        TlsHandshakeType::CertificateRequest => parse_tls_handshake_msg_certificaterequest(raw_msg),
        TlsHandshakeType::ServerDone => parse_tls_handshake_msg_serverdone(raw_msg, hl as usize),
        TlsHandshakeType::CertificateVerify => {
            parse_tls_handshake_msg_certificateverify(raw_msg, hl as usize)
        }
        TlsHandshakeType::ClientKeyExchange => {
            parse_tls_handshake_msg_clientkeyexchange(raw_msg, hl as usize)
        }
        TlsHandshakeType::Finished => parse_tls_handshake_msg_finished(raw_msg, hl as usize),
        // TlsHandshakeType::CertificateURL => parse_tls_handshake_msg_certificateurl(raw_msg),
        TlsHandshakeType::CertificateStatus => parse_tls_handshake_msg_certificatestatus(raw_msg),
        TlsHandshakeType::KeyUpdate => parse_tls_handshake_msg_key_update(raw_msg),
        TlsHandshakeType::NextProtocol => parse_tls_handshake_msg_next_protocol(raw_msg),
        _ => Err(Err::Error(make_error(i, ErrorKind::Switch))),
    }?;
    Ok((i, TlsMessage::Handshake(msg)))
}

/// Parse a TLS changecipherspec message
// XXX add extra verification hdr.len == 1
pub fn parse_tls_message_changecipherspec(i: &[u8]) -> IResult<&[u8], TlsMessage> {
    let (i, _) = verify(be_u8, |&tag| tag == 0x01)(i)?;
    Ok((i, TlsMessage::ChangeCipherSpec))
}

/// Parse a TLS alert message
// XXX add extra verification hdr.len == 2
pub fn parse_tls_message_alert(i: &[u8]) -> IResult<&[u8], TlsMessage> {
    let (i, alert) = TlsMessageAlert::parse(i)?;
    Ok((i, TlsMessage::Alert(alert)))
}

/// Parse a TLS applicationdata message
///
/// Read the entire input as applicationdata
pub fn parse_tls_message_applicationdata(i: &[u8]) -> IResult<&[u8], TlsMessage> {
    let msg = TlsMessage::ApplicationData(TlsMessageApplicationData { blob: i });
    Ok((&[], msg))
}

/// Parse a TLS heartbeat message
pub fn parse_tls_message_heartbeat(
    i: &[u8],
    tls_plaintext_len: u16,
) -> IResult<&[u8], Vec<TlsMessage>> {
    let (i, heartbeat_type) = TlsHeartbeatMessageType::parse(i)?;
    let (i, payload_len) = be_u16(i)?;
    if tls_plaintext_len < 3 {
        return Err(Err::Error(make_error(i, ErrorKind::Verify)));
    }
    let (i, payload) = take(payload_len as usize)(i)?;
    let v = vec![TlsMessage::Heartbeat(TlsMessageHeartbeat {
        heartbeat_type,
        payload_len,
        payload,
    })];
    Ok((i, v))
}

/// Given data and a TLS record header, parse content.
///
/// A record can contain multiple messages (with the same type).
///
/// Note that message length is checked (not required for parser safety, but for
/// strict protocol conformance).
#[rustfmt::skip]
#[allow(clippy::trivially_copy_pass_by_ref)] // TlsRecordHeader is only 6 bytes, but we prefer not breaking current API
pub fn parse_tls_record_with_header<'i, 'hdr>(i:&'i [u8], hdr:&'hdr TlsRecordHeader ) -> IResult<&'i [u8], Vec<TlsMessage<'i>>> {
    match hdr.record_type {
        TlsRecordType::ChangeCipherSpec => many1(complete(parse_tls_message_changecipherspec))(i),
        TlsRecordType::Alert            => many1(complete(parse_tls_message_alert))(i),
        TlsRecordType::Handshake        => many1(complete(parse_tls_message_handshake))(i),
        TlsRecordType::ApplicationData  => many1(complete(parse_tls_message_applicationdata))(i),
        TlsRecordType::Heartbeat        => parse_tls_message_heartbeat(i, hdr.len),
        _                               => Err(Err::Error(make_error(i, ErrorKind::Switch)))
    }
}

/// Parse one packet only, as plaintext
/// A single record can contain multiple messages, they must share the same record type
pub fn parse_tls_plaintext(i: &[u8]) -> IResult<&[u8], TlsPlaintext> {
    let (i, hdr) = parse_tls_record_header(i)?;
    if hdr.len > MAX_RECORD_LEN {
        return Err(Err::Error(make_error(i, ErrorKind::TooLarge)));
    }
    let (i, msg) = map_parser(take(hdr.len as usize), |i| {
        parse_tls_record_with_header(i, &hdr)
    })(i)?;
    Ok((i, TlsPlaintext { hdr, msg }))
}

/// Parse one packet only, as encrypted content
pub fn parse_tls_encrypted(i: &[u8]) -> IResult<&[u8], TlsEncrypted> {
    let (i, hdr) = parse_tls_record_header(i)?;
    if hdr.len > MAX_RECORD_LEN {
        return Err(Err::Error(make_error(i, ErrorKind::TooLarge)));
    }
    let (i, blob) = take(hdr.len as usize)(i)?;
    let msg = TlsEncryptedContent { blob };
    Ok((i, TlsEncrypted { hdr, msg }))
}

/// Read TLS record envelope, but do not decode data
///
/// This function is used to get the record type, and to make sure the record is
/// complete (not fragmented).
/// After calling this function, use `parse_tls_record_with_header` to parse content.
pub fn parse_tls_raw_record(i: &[u8]) -> IResult<&[u8], TlsRawRecord> {
    let (i, hdr) = parse_tls_record_header(i)?;
    if hdr.len > MAX_RECORD_LEN {
        return Err(Err::Error(make_error(i, ErrorKind::TooLarge)));
    }
    let (i, data) = take(hdr.len as usize)(i)?;
    Ok((i, TlsRawRecord { hdr, data }))
}

/// Parse one packet only, as plaintext
/// This function is deprecated. Use `parse_tls_plaintext` instead.
///
/// This function will be removed from API, as the name is not correct: it is
/// not possible to parse TLS packets without knowing the TLS state.
#[deprecated(since = "0.5.0", note = "Use parse_tls_plaintext")]
#[inline]
pub fn tls_parser(i: &[u8]) -> IResult<&[u8], TlsPlaintext> {
    parse_tls_plaintext(i)
}

/// Parse one chunk of data, possibly containing multiple TLS plaintext records
/// This function is deprecated. Use `parse_tls_plaintext` instead, checking if
/// there are remaining bytes, and calling `parse_tls_plaintext` recursively.
///
/// This function will be removed from API, as it should be replaced by a more
/// useful one to handle fragmentation.
pub fn tls_parser_many(i: &[u8]) -> IResult<&[u8], Vec<TlsPlaintext>> {
    many1(complete(parse_tls_plaintext))(i)
}