Now each address has its own errors count, so rspamd will prefer upstream addrs with no errors to addrs with errors. This might help to resolve issues on systems where ipv6 does not work.
- Select ipv4/unix addresses if they exist and use ipv6 for ipv6 only
upstreams (since the support of ipv6 is poor in many OSes and
environments).
- Free IP list on upstream destruction.
- Add test cases for addresses selection.
- Allow adding of free form IP addresses to upstreams.
P value is calculated as following:
when we add/remove M upstreams from the list, the probability of hash
miss should be close to the relation N / (N + M), where N is the size of
the previous upstreams list.
So far, the algorithm described in http://arxiv.org/abs/1406.2294 shows
p value more than 0.99.