>Deep Packet Inspection

>WireGuard does not focus on obfuscation. Obfuscation, rather, should happen at a layer above WireGuard, with WireGuard focused on providing solid crypto with a simple implementation. It is quite possible to plug in various forms of obfuscation, however.

>TCP Mode

>WireGuard explicitly does not support tunneling over TCP, due to the classically terrible network performance of tunneling TCP-over-TCP. Rather, transforming WireGuard's UDP packets into TCP is the job of an upper layer of obfuscation (see previous point), and can be accomplished by projects like udptunnel and udp2raw.

The initiator sends this message:

  msg = handshake_initiation {
    u8 message_type
    u8 reserved_zero[3]
    u32 sender_index
    u8 unencrypted_ephemeral[32]
    u8 encrypted_static[AEAD_LEN(32)]
    u8 encrypted_timestamp[AEAD_LEN(12)]
    u8 mac1[16]
    u8 mac2[16]
  }

  msg.message_type = 1
  msg.reserved_zero = { 0, 0, 0 }

     * Heuristics to detect the WireGuard protocol:
     * - The first byte must be one of the valid four messages.
     * - The total packet length depends on the message type, and is fixed for
     *   three of them. The Data type has a minimum length however.
     * - The next three bytes are reserved and zero in the official protocol.
     *   Cloudflare's implementation however uses this field for load balancing
     *   purposes, so this condition is not checked here for most messages.
     *   It is checked for data messages to avoid false positives.