Adding regex support in the IP whitelist

[mattk42]

These changes add support for regex values in the ip whitelist config, identified by a leading tilda (~). This is useful in cases where you want to allow all traffic from a specific subnet to access elasticsearch without authentication.

This was accomplished by implementing the whitelist as an object array and then checking the types and doing what is appropriate in the contains methods.

[Xylakant]

I support the idea, but if we want to provide that functionality we should really use proper CIDR notation with a netmask.

[mattk42]

I do agree, I hacked this together yesterday to get a project I am working on moving. But I did realize afterwards that CIDR would have been nice.

Looks like Apache's SubnetUtils library will make this easy (http://commons.apache.org/proper/commons-net/apidocs/org/apache/commons/net/util/SubnetUtils.SubnetInfo.html). I will take a look at moving to that in the next week or so.

[emig]

@mattk42 There is this PR #33 with misleading title that allows CIDR on the whitelist. Was planning to take a look at it tomorrow and eventually merge it

[mattk42]

Ah, must have missed that one. That works for me, I'll go ahead and close this PR. Thanks!