Questions about PF_KEY interface

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Dear all:

I found there are two directories about PF_KEY interface: netkey and 
netipsec under $FreeBSD src$\sys\.

Looking into the makefile, the one that is currently used and built in 
is netkey.

However, I am wondering what's the purpose for netipsec?

Besides, the handling for the global variable "regtree", which is used 
for key registery, in netipsec seems more proper to me.

For example, when a key is needed to register, the static function, 
key_register(), which is defined in [netkey/netipsec]/key.c, will be called.

However, in netkey/key.c, key_register() will not call mtx_lock before 
the operation of the global variable, regtree. On the other hand, in 
netipsec/key.c, key_register() will mtx_lock. In my opinion, I think the 
latter should be correct since there may be various processes to call 
the function. Without the protection, race condition will occur!

Many thanks.

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