Add a azure-ip-range function

This function get the list of IP addresses associated with the named
Microsoft Azure service.

```
pass in proto tcp from azure-ip-range('DataFactory.FranceCentral') to any port 5432
```

lib/puffy/parser.y

@@ -148,8 +148,9 @@ rule
            | host_list host_list_item     { result = val[0] + val[1] }
            | host_list_item               { result = val[0] }
 
-  host_list_item: host     { result = [val[0]] }
-                | VARIABLE { result = @variables.fetch(val[0][:value]) }
+  host_list_item: host                          { result = [val[0]] }
+                | VARIABLE                      { result = @variables.fetch(val[0][:value]) }
+                | AZURE_IP_RANGE '(' STRING ')' { result = Resolver.instance.resolv_azure_ip_range(val[2][:value]) }
 
   filteropts: filteropts ',' filteropt  { result = val[0].merge(val[2]) }
             | filteropts filteropt      { result = val[0].merge(val[1]) }
@@ -164,6 +165,7 @@ end
 
 require 'deep_merge'
 require 'ipaddr'
+require 'json'
 require 'strscan'
 
 ---- inner
@@ -250,6 +252,7 @@ require 'strscan'
       when s.scan(/rdr-to\b/) then  emit(:RDR_TO, s.matched)
       when s.scan(/srv\b/) then     emit(:SRV, s.matched)
       when s.scan(/apt-mirror\b/) then emit(:APT_MIRROR, s.matched)
+      when s.scan(/azure-ip-range\b/) then emit(:AZURE_IP_RANGE, s.matched)
 
       when s.scan(/\d+\.\d+\.\d+\.\d+(\/\d+)?/) && ip = ipaddress?(s) then           emit(:ADDRESS, ip, s.matched_size)
       when s.scan(/[[:xdigit:]]*:[:[:xdigit:]]+(\/\d+)?/) && ip = ipaddress?(s) then emit(:ADDRESS, ip, s.matched_size)

lib/puffy/resolver.rb

@@ -56,6 +56,14 @@ def resolv_apt_mirror(url)
       res
     end
 
+    def resolv_azure_ip_range(service_name)
+      # https://www.microsoft.com/en-us/download/details.aspx?id=56519
+      @azure_ip_range ||= JSON.parse(URI('https://download.microsoft.com/download/7/1/D/71D86715-5596-4529-9B13-DA13A5DE5B63/ServiceTags_Public_20240701.json').read)
+
+      res = @azure_ip_range['values'].select { |service| service['name'] == service_name }[0]['properties']['addressPrefixes']
+      res.map { |ip| IPAddr.new(ip) }
+    end
+
     private
 
     def parse_url(url)

spec/puffy/resolver_spec.rb

@@ -56,5 +56,15 @@ module Puffy
                                                                                        ])
       end
     end
+
+    describe '#resolv_azure_ip_range' do
+      it 'works' do
+        res = subject.resolv_azure_ip_range('ActionGroup')
+
+        expect(res).to be_an(Array)
+        expect(res).not_to be_empty
+        expect(res.first).to be_an(IPAddr)
+      end
+    end
   end
 end