ControlMessageOwned::UdpGroSegments size mismatches the actual size

[zhaiyan920]

UdpGroSegments is declared as a u16 cmsg in the library but the Linux kernel actually puts an int in the cmsg:

https://elixir.bootlin.com/linux/latest/source/include/linux/udp.h#L145

So applications using this option will break on big endian Linux machines. To fix it, the size may need to be adjusted to the size of an int for related kernel versions (doubt kernel maintainers might not change this in hope to not break user space: https://lore.kernel.org/netdev/CANn89iL2PCnC=6dOrozW0309W==tWcKpj2iwZgZAD_s0amvzLA@mail.gmail.com/T/)

[SteveLauC]

IIUC, the Linux kernel itself is still using an unsigned short to store the gso_size, e.g., this one, it is just the (userspace) interfaces that are not using the correct type?