udpcmsg

func CmsgPktInfo ¶

func CmsgPktInfo(b []byte, addr netip.Addr) []byte

Pack addr into a control msg (Inet[4|6]Pktinfo). b is the buffer for packing, if b is not big enough (or nil), a new slice will be allocated. Invalid addr returns nil.

func CmsgSize ¶

func CmsgSize(addr netip.Addr) int

Cmsg size for addr. If addr is invalid, returns 0.

func Ok ¶

func Ok() bool

func ParseLocalAddr ¶

func ParseLocalAddr(oob []byte) (netip.Addr, error)

Parses local addr from oob control msgs. May return invalid addr and nil error if no local addr info was found.

func SetOpt ¶

func SetOpt(c *net.UDPConn) (inet6 bool, err error)

Set socket option to receive local addr in oob. Inet6 is true if c is an inet6 connection and IPV6_RECVPKTINFO was set. otherwise, c is an inet4 connection and IP_PKTINFO was set.