HelenOS sources

root/uspace/lib/inet/include/inet/

[..]
addr.h dhcp.h dnsr.h endpoint.h eth_addr.h
host.h hostname.h hostport.h inet.h inetcfg.h
inetping.h iplink.h iplink_srv.h tcp.h udp.h
[..]
HelenOS homepage, sources at GitHub