Module openvpn 

OpenVPN Protocol Implementation

Implements the OpenVPN control and data channel protocols, including:

• Packet opcodes and header parsing (P_CONTROL, P_DATA, P_ACK)
• TLS-Auth pre-shared HMAC authentication
• Client state machine (Initial -> TLS -> Auth -> Connected)
• Packet ID anti-replay protection (sliding window)
• Configuration file parsing (key=value format)

Structs

OpenvpnClient

OpenVPN client connection

OpenvpnConfig

OpenVPN client/server configuration

OpenvpnHeader

Parsed OpenVPN packet header

PacketIdWindow

Sliding-window anti-replay protection for packet IDs

TlsAuth

TLS-Auth pre-shared HMAC key for control channel authentication

Enums

AuthAlgorithm

HMAC authentication algorithm (for non-AEAD ciphers)

CipherAlgorithm

Data channel cipher algorithm

Compression

Compression algorithm

OpenvpnError

OpenVPN protocol error

OpenvpnOpcode

OpenVPN packet opcodes (5 bits, high nibble of first byte)

OpenvpnState

Client connection state

TransportProto

Transport protocol for the tunnel

Constants

DEFAULT_PORT

Default OpenVPN UDP port

Functions

parse_config

Parse an OpenVPN-style configuration from key=value lines.