IsPrivateAddress returns whether an IP address belongs to the LAN.

ListenUDP wraps Go's net.ListenConfig.ListenPacket and sets socket options on supported platforms.

NewAddr returns a net.Addr that holds an address of the form `host:port` with a domain name or IP as host.

ParseFlagsForError parses the message flags returned by the ReadMsgUDPAddrPort method and returns an error if MSG_TRUNC is set, indicating that the returned packet was truncated.

Relay copies between left and right bidirectionally.

RequirePublicIP returns an error if the destination IP is not a standard public IP.

UpdateOobCache filters out irrelevant OOB messages, saves IP_PKTINFO or IPV6_PKTINFO socket control messages to the OOB cache, and returns the updated OOB cache slice.

WrapDuplexConn wraps an existing DuplexConn with new Reader and Writer, but preserving the original CloseRead() and CloseWrite().

UDPOOBBufferSize specifies the size of buffer to allocate for receiving OOB data when calling the ReadMsgUDP method on a *net.UDPConn returned by this package's ListenUDP function.

DuplexConn is a net.Conn that allows for closing only the reader or writer end of it, supporting half-open state.

TargetIPValidator is a type alias for checking if an IP is allowed.