module BBS::Address

What an IP address is: a caller’s own line on the internet, or one of the board’s neighbours (a proxy on the Docker network, the loopback).

BBS::Address.local?('172.18.0.5')    # => true  (bbs-web on the stack)
BBS::Address.public?('100.64.1.2')   # => false (carrier-grade NAT)

Constants

NON_PUBLIC: The ranges that are not on the public internet beyond what IPAddr tells (private, loopback, link-local): this network, carrier-grade NAT, the IETF, documentation and benchmark ranges, multicast and the reserved block, IPv6 unspecified, IPv4-translated, discard, documentation and multicast.

Public Instance Methods

local? (ip)

Source

# File lib/bbs/address.rb, line 36
def local?(ip)
  addr = parse(ip) or return false
  addr.private? || addr.loopback? || addr.link_local?
end

Returns whether ip is a neighbour of the board: a private, loopback or link-local address (IPv6 unique local included). false for anything that is not an IP address.

parse (ip)

Source

# File lib/bbs/address.rb, line 27
def parse(ip)
  (ip.is_a?(IPAddr) ? ip : IPAddr.new(ip.to_s)).native
rescue IPAddr::Error
  nil
end

Returns ip (a String or an IPAddr) as an IPAddr, an IPv4-mapped IPv6 address as its IPv4 one; nil when it is not an IP address.

public? (ip)

Source

# File lib/bbs/address.rb, line 44
def public?(ip)
  addr = parse(ip) or return false
  !local?(addr) && NON_PUBLIC.none? { |range| range.family == addr.family && range.include?(addr) }
end

Returns whether ip is an address on the public internet: not local? and in none of the NON_PUBLIC ranges. false for anything that is not an IP address.