struct iphdr中的__LITTLE_ENDIAN_BITFIELD和__BIG_ENDIAN_BITFIELD
__LITTLE_ENDIAN_BITFIELD表示小端序,__BIG_ENDIAN_BITFIELD表示大端序。/usr/include/linux/ip.h中有一段代码定义了ip首部的结构体,如下:structiphdr{#ifdefined(__LITTLE_ENDIAN_BITFIELD)__u8ihl:4,version:4;#elifdefined(__BIG_ENDIAN_BITFI