nathole

var (
	// mode 0: simple detect mode, usually for both EasyNAT or HardNAT & EasyNAT(Public Network)
	// a. receiver sends detect message with low TTL
	// b. sender sends normal detect message to receiver
	// c. receiver receives detect message and sends back a message to sender
	//
	// mode 1: For HardNAT & EasyNAT, send detect messages to multiple guessed ports.
	// Usually applicable to scenarios where port changes are regular.
	// Most of the steps are the same as mode 0, but EasyNAT is fixed as the receiver and will send detect messages
	// with low TTL to multiple guessed ports of the sender.
	//
	// mode 2: For HardNAT & EasyNAT, ports changes are not regular.
	// a. HardNAT machine will listen on multiple ports and send detect messages with low TTL to EasyNAT machine
	// b. EasyNAT machine will send detect messages to random ports of HardNAT machine.
	//
	// mode 3: For HardNAT & HardNAT, both changes in the ports are regular.
	// Most of the steps are the same as mode 1, but the sender also needs to send detect messages to multiple guessed
	// ports of the receiver.
	//
	// mode 4: For HardNAT & HardNAT, one of the changes in the ports is regular.
	// Regular port changes are usually on the sender side.
	// a. Receiver listens on multiple ports and sends detect messages with low TTL to the sender's guessed range ports.
	// b. Sender sends detect messages to random ports of the receiver.
	SupportedModes = []int{DetectMode0, DetectMode1, DetectMode2, DetectMode3, DetectMode4}
	SupportedRoles = []string{DetectRoleSender, DetectRoleReceiver}

	DetectMode0        = 0
	DetectMode1        = 1
	DetectMode2        = 2
	DetectMode3        = 3
	DetectMode4        = 4
	DetectRoleSender   = "sender"
	DetectRoleReceiver = "receiver"
)

var NatHoleTimeout int64 = 10