struct ifreq

cbm19851015

The ifreq structure is defined in /usr/include/net/if.h, which is used to configure the ip address, activate the interface, configure the MTU and other interface information.
It contains the name and specific content of an interface-(it is a community, which may be an IP address, broadcast address, subnet mask, MAC number, MTU or other content).
ifreq is contained in the ifconf structure. The ifconf structure is usually used to store all interface information.

If you want to learn more, I recommend the following URL, which explains in great detail:
http://tech.sunplusedu.com/space/post-4064.aspx