Proposed patch for Port Randomization modifications according to RFC6056

[Bjoern A. Zeeb]

On Wed, 26 Jan 2011, Ivo Vachkov wrote:

Hi,

> I would like to propose a patch (against FreeBSD RELENG_8) to extend
> the port randomization support in FreeBSD, according to RFC6056
> (https://www.rfc-editor.org/rfc/rfc6056.txt)
>
> Currently the patch implements:
> - Algorithm 1 (default in FreeBSD 8)
> - Algorithm 2
> - Algorithm 5
> from the aforementioned RFC6056.
>
> Any of those algorithms can be chosen with the sysctl variable
> net.inet.ip.portrange.rfc6056_algorithm.
>
> I deliberately skipped Algorithm 3 and Algorithm 4, because I believe
> usage of cryptographic hash functions will introduce unnecessary
> latency in vital network operations. However, in case of expressed
> interest, I will be glad to add those too.
>
> I would like to ask what is the proper way to validate the sysctl
> input in order to accept only a specific values? In my case only '1',
> '2' and '5'.
>
> Thank you very much.

It needs to be implemented in sys/netinet6/in6_src.c as well.  Given
the growth I wonder if we can design it more intelligent to avoid more
code duplication for 3 (to 5) alogrithms, especially considering, that
syncing between legacy and ipv6 has failed in the past.

/bz

-- 
Bjoern A. Zeeb                                 You have to have visions!
         <ks> Going to jail sucks -- <bz> All my daemons like it!
   http://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/jails.html