customise ipasn service

Add a `custom_api` configuration parameter to allow for customisation of the [IPASN-History](https://github.com/D4-project/IPASN-History) instance queried.

Default use of `https://ipasnhistory.circl.lu/` is preserved.

misp_modules/modules/expansion/ipasn.py

@@ -20,6 +20,9 @@
     'input': 'An IP address MISP attribute.',
     'output': 'Asn object(s) objects related to the IP address used as input.',
 }
+moduleconfig = [
+    "custom_api"
+]
 
 
 def parse_result(attribute, values):
@@ -53,7 +56,9 @@ def handler(q=False):
 
     toquery = request['attribute']['value']
 
-    ipasn = IPASNHistory()
+    ipasn_url = request["config"].get("custom_api") or "https://ipasnhistory.circl.lu/"
+
+    ipasn = IPASNHistory(root_url=ipasn_url)
     values = ipasn.query(toquery)
 
     if not values:
@@ -67,4 +72,5 @@ def introspection():
 
 
 def version():
+    moduleinfo["config"] = moduleconfig
     return moduleinfo