.ovpn file parser

[cachebag]

part of #288.

changes

new file: core/ovpn_parser.rs

parse .ovpn config files into a structured OvpnFile type. the format is one openvpn CLI option per line with inline cert blocks delimited by xml-style tags (<ca>...</ca>).

key directives to handle:

• remote <host> [port] [proto] (can appear multiple times)
• port, proto tcp|udp, dev tun|tap
• auth-user-pass (implies password auth)
• ca, cert, key — file paths or inline blocks
• tls-auth, tls-crypt, tls-crypt-v2
• cipher, data-ciphers, auth
• redirect-gateway, route
• compress, comp-lzo

output types:

pub struct OvpnFile {
    pub remotes: Vec<OvpnRemote>,
    pub protocol: Option<OvpnProtocol>,
    pub port: Option<u16>,
    pub auth_type: OpenVpnAuthType,  // inferred
    pub ca: Option<CertSource>,
    pub cert: Option<CertSource>,
    pub key: Option<CertSource>,
    pub tls_auth: Option<TlsAuthConfig>,
    pub tls_crypt: Option<CertSource>,
    pub cipher: Option<String>,
    pub data_ciphers: Option<String>,
    pub auth_digest: Option<String>,
    pub compress: Option<String>,
    pub mtu: Option<u32>,
    pub routes: Vec<OvpnRoute>,
    pub redirect_gateway: bool,
    pub extra_options: HashMap<String, String>,
}

pub enum CertSource {
    Path(String),
    Inline(String),
}

tests

embed sample .ovpn content as &str constants. test cases:

• password auth ovpn
• tls-only with inline certs
• password+tls with file-path certs
• multiple remote directives
• redirect-gateway
• comments, blank lines, unknown directives (graceful)
• malformed input (proper errors)