In order for Dhcp6AppendIaAddrOption (..) to safely append the IA Address option, the Packet-Length field must be updated before appending the option. Cc: Saloni Kasbekar <saloni.kasbekar@intel.com> Cc: Zachary Clark-williams <zachary.clark-williams@intel.com> Signed-off-by: Doug Flick [MSFT] <doug.edk2@gmail.com> Reviewed-by: Saloni Kasbekar <saloni.kasbekar@intel.com> Reviewed-by: Leif Lindholm <quic_llindhol@quicinc.com>