GRE with key

[Bruce M. Simpson]

Cristian KLEIN wrote:
> Hello everybody,
>
> I am new to FreeBSD kernel hacking, so please excuse my perhaps stupid
> questions.
>
> I would like to add key support to gre(4). I have already been able to
> use gre(4) with a hardcoded key. The single thing remaining to do is to
> transfer the key from ifconfig(8). The key is an uint32_t and I haven't
> found a way to transfer it without modifying ifconfig(8).
>   
Excellent. Thanks for volunteering to do this!
> My question is, which is the "BSD-style" to achieve the above? Solutions
> I came up with are as follows:
> 1) Use SIOCSDRVSPEC / SIOCGDRVSPEC
> 2) Add SIOCSGREKEY / SIOCGGREKEY
> 3) [Probably to ugly to be mentioned, but requires fairy few
> modifications.] Add a sysctl MIB which is read when calling "ifconfig
> ... create".
>   
If I were doing this, I would add the code to ifconfig.c where the other 
tunnel stuff lives, and go for option number 2. Feel free to modify 
ifconfig to accomodate the the new options.
> Another thing I wanted to ask is, which function of ifconfig(8) should I
> modify to display the GRE key?
>   
Look at how af_status_tunnel() works and consider adding it there.

Regards,
BMS