class OpenSSL::SSL::SSLSocket

def post_connection_check(hostname)
  check_common_name = true
  cert = peer_cert
  cert.extensions.each{|ext|
    next if ext.oid != "subjectAltName"
    ext.value.split(/,\s+/).each{|general_name|
      if /\ADNS:(.*)/ =~ general_name
        check_common_name = false
        reg = Regexp.escape($1).gsub(/\\\*/, "[^.]+")
        return true if /\A#{reg}\z/i =~ hostname
      elsif /\AIP Address:(.*)/ =~ general_name
        check_common_name = false
        return true if $1 == hostname
      end
    }
  }
  if check_common_name
    cert.subject.to_a.each{|oid, value|
      if oid == "CN"
        reg = Regexp.escape(value).gsub(/\\\*/, "[^.]+")
        return true if /\A#{reg}\z/i =~ hostname
      end
    }
  end
  raise SSLError, "hostname not match"
end