Function socketControlMessageTimestamp

timestamp/timestamp_linux.go:268–282

socketControlMessageTimestamp is a very optimised version of ParseSocketControlMessage https://github.com/golang/go/blob/2ebe77a2fda1ee9ff6fd9a3e08933ad1ebaea039/src/syscall/sockcmsg_unix.go#L40 which only parses the timestamp message type

(b []byte, boob int)

	mlen := 0
	for i := 0; i < boob; i += unix.CmsgSpace(mlen - unix.SizeofCmsghdr) {
		h := (*unix.Cmsghdr)(unsafe.Pointer(&b[i]))
		mlen = int(h.Len) //#nosec G115
		if mlen == 0 {
			break
		}
		// depending on the kernel version, when we ask for SO_TIMESTAMPING_NEW we still might get messages with type SO_TIMESTAMPING
		if h.Level == unix.SOL_SOCKET && int(h.Type) == unix.SO_TIMESTAMPING_NEW || int(h.Type) == unix.SO_TIMESTAMPING {
			return scmDataToTime(b[i+socketControlMessageHeaderOffset : i+mlen])
		}
	}
	return time.Time{}, ErrNoTimestamp
}

// socketControlMessageDrops parses SocketControlMessage for drops count
// drops are provided by SO_RXQ_OVFL control message when enabled
func socketControlMessageDrops(b []byte, boob int) uint32 {
	mlen := 0
	var drops uint32