Add resolver edns options

1 files changed, 49 insertions, 0 deletions

diff --git a/examples/edns_resolver.py b/examples/edns_resolver.py
new file mode 100644
index 0000000..fe5cc0f
--- /dev/null
+++ b/examples/edns_resolver.py
@@ -0,0 +1,49 @@
+#!/usr/bin/env python3
+
+import dns.edns
+import dns.message
+import dns.query
+import dns.resolver
+
+n = '.'
+t = dns.rdatatype.SOA
+l = 'google.com'  # Address of l.root-servers.net, '199.7.83.42'
+i = 'ns1.isc.org'  # Address of ns1.isc.org, for COOKIEs, '149.20.1.73'
+
+o_list = []
+
+# A query without options
+o_list.append((l, dict()))
+
+# The same query, but with empty options list
+o_list.append((l, dict(options=[])))
+
+# Use use_edns() to specify EDNS0 options, such as buffer size
+o_list.append((l, dict(payload=2000)))
+
+# With an NSID option, but with use_edns() to specify the options
+edns_kwargs = dict(edns=0, options=[
+    dns.edns.GenericOption(dns.edns.OptionType.NSID, b'')])
+o_list.append((l, edns_kwargs))
+
+# With a COOKIE
+o_list.append((i, dict(options=[
+    dns.edns.GenericOption(dns.edns.OptionType.COOKIE, b'0xfe11ac99bebe3322')])))
+
+# With an ECS option using cloudflare dns address
+o_list.append((l, dict(options=[dns.edns.ECSOption('1.1.1.1', 24)])))
+
+# With an ECS option using the current machine address
+import urllib.request
+
+external_ip = urllib.request.urlopen('https://ident.me').read().decode('utf8')
+
+o_list.append((l, dict(options=[dns.edns.ECSOption(external_ip, 24)])))
+
+aresolver = dns.resolver.Resolver()
+
+for (addr, edns_kwargs) in o_list:
+    if edns_kwargs:
+        aresolver.use_edns(**edns_kwargs)
+    aresolver.nameservers = ['8.8.8.8']
+    print(list(aresolver.resolve(addr, 'A')))