frameassembly 1.2.1

Declarative Rust DSL and compiler to generate deterministic .pcap/.pcapng packet captures across 81 L2-L7 protocols for Wireshark, IDS & CI testing.
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//! Transport Layer Security (TLS 1.2 and TLS 1.3) Layer 7 record and handshake field parser.
//!
//! This module implements the `winnow` parser combinator for RFC 5246 and RFC 8446 `TLS` record
//! and handshake messages in FrameAssembly `.fasm` specifications. It recognizes the `TLS`
//! protocol keyword, record/handshake message flags (`CLIENT_HELLO`, `SERVER_HELLO`,
//! `CERTIFICATE`, `FINISHED`, `APP_DATA`, `ALERT`), TLS record and handshake versions
//! (`RECORD_VERSION`, `HANDSHAKE_VERSION`), Server Name Indication (`SNI`), cipher suite IDs
//! (`CIPHERSUITE`), and Application-Layer Protocol Negotiation strings (`ALPN`).

use winnow::ModalResult as PResult;
use winnow::combinator::{alt, cut_err};
use winnow::prelude::*;

use crate::ast::*;
use crate::lexer::Token;
use crate::parser::{parse_str_val, parse_u32, tag, ParsedField, Stream};

/// Parses a TLS protocol declaration or handshake/record field.
pub(crate) fn parse_tls_field<'i, 'a>(input: &mut Stream<'i, 'a>) -> PResult<ParsedField<'a>> {
    alt((
        alt((
            tag(Token::Tls).map(|(_, s)| ParsedField::Protocol(Protocol::Tls, (s.start, s.len()))),
            tag(Token::ClientHello)
                .map(|(_, s)| ParsedField::L7Flag("CLIENT_HELLO", (s.start, s.len()))),
            tag(Token::ServerHello)
                .map(|(_, s)| ParsedField::L7Flag("SERVER_HELLO", (s.start, s.len()))),
            tag(Token::Certificate)
                .map(|(_, s)| ParsedField::L7Flag("CERTIFICATE", (s.start, s.len()))),
            tag(Token::Finished).map(|(_, s)| ParsedField::L7Flag("FINISHED", (s.start, s.len()))),
            tag(Token::AppData).map(|(_, s)| ParsedField::L7Flag("APP_DATA", (s.start, s.len()))),
        )),
        alt((
            tag(Token::Alert).map(|(_, s)| ParsedField::L7Flag("ALERT", (s.start, s.len()))),
            (tag(Token::RecordVersion), cut_err(parse_u32)).map(|((_, s), v)| {
                ParsedField::L7U32Field("RECORD_VERSION", v, (s.start, s.end - s.start))
            }),
            (tag(Token::HandshakeVersion), cut_err(parse_u32)).map(|((_, s), v)| {
                ParsedField::L7U32Field("HANDSHAKE_VERSION", v, (s.start, s.end - s.start))
            }),
            (tag(Token::Sni), cut_err(parse_str_val))
                .map(|((_, s), v)| ParsedField::L7StringField("SNI", v, (s.start, s.end - s.start))),
            (tag(Token::Ciphersuite), cut_err(parse_u32)).map(|((_, s), v)| {
                ParsedField::L7U32Field("CIPHERSUITE", v, (s.start, s.end - s.start))
            }),
            (tag(Token::Alpn), cut_err(parse_str_val)).map(|((_, s), v)| {
                ParsedField::L7StringField("ALPN", v, (s.start, s.end - s.start))
            }),
        )),
    ))
    .parse_next(input)
}