linux

const (
	TCPI_OPT_TIMESTAMPS = 1  // TCP timestamps were enabled
	TCPI_OPT_SACK       = 2  // SACK was enabled
	TCPI_OPT_WSCALE     = 4  // TCP window scaling was used
	TCPI_OPT_ECN        = 8  // ECN was negotiated at TCP session init
	TCPI_OPT_ECN_SEEN   = 16 // we received at least one packet with ECT
	TCPI_OPT_SYN_DATA   = 32 // SYN-ACK acked data in SYN sent or rcvd
)