Got this socket error while implementing dtls in contiki

[pdhage-dev]

../../apps/tinydtls/session.h:45:10: fatal error: sys/socket.h: No such file or directory #include <sys/socket.h> ^~~~~~~~~~~~~~ compilation terminated. ../../Makefile.include:240: recipe for target 'obj_srf06-cc26xx/dtls.o' failed make: *** [obj_srf06-cc26xx/dtls.o] Error 1
I want to implement the dtls security for contiki and I am following this steps
https://sunmaysky.blogspot.com/search/label/DTLS