Compile xfrm has module

Hi 
I am trying to compile xfrm has modules that can be inserted during run time , 
I am able to compile but compile it But I found there are few issue inserting the modules.
I have edited the Make file in net/xfrm to refelect the below , there are few undefined references .
Is it polible to build XFRM itself has a module , please guide me on the same.

root@qabng249c:/usr/src/linux-2.6.34# cat net/xfrm/Makefile
#
# Makefile for the XFRM subsystem.
#

obj-m := xfrm_policy.o xfrm_state.o xfrm_hash.o \
                      xfrm_input.o xfrm_output.o xfrm_algo.o \
                      xfrm_sysctl.o
obj-n += xfrm_proc.o
obj-m += xfrm_user.o
obj-m += xfrm_ipcomp.o

Thanks and Regards
Naveen