/usr/arm-linux-gnueabihf/include/netinet/ is in libc6-dev-armhf-cross 2.27-3ubuntu1cross1.
This file is owned by root:root, with mode 0o755.
..
/usr/arm-linux-gnueabihf/include/netinet/ether.h
/usr/arm-linux-gnueabihf/include/netinet/icmp6.h
/usr/arm-linux-gnueabihf/include/netinet/if_ether.h
/usr/arm-linux-gnueabihf/include/netinet/if_fddi.h
/usr/arm-linux-gnueabihf/include/netinet/if_tr.h
/usr/arm-linux-gnueabihf/include/netinet/igmp.h
/usr/arm-linux-gnueabihf/include/netinet/in.h
/usr/arm-linux-gnueabihf/include/netinet/in_systm.h
/usr/arm-linux-gnueabihf/include/netinet/ip.h
/usr/arm-linux-gnueabihf/include/netinet/ip6.h
/usr/arm-linux-gnueabihf/include/netinet/ip_icmp.h
/usr/arm-linux-gnueabihf/include/netinet/tcp.h
/usr/arm-linux-gnueabihf/include/netinet/udp.h