struct
struct IpAddr
A v4 or v6 address. kind is 4 or 6; the other fields are meaningful only for the matching kind.
V4 layout: v4 holds the 32-bit address in host-order, e.g. 127.0.0.1 is 0x7F000001.
V6 layout: v6_hi and v6_lo are the upper and lower 64 bits in host-order. The address ::1 has v6_hi = 0, v6_lo = 1.