From 8de87255bfea0b07742f5d017327f1a374c69dc1 Mon Sep 17 00:00:00 2001
From: Bob Halley <halley@dnspython.org>
Date: Mon, 4 May 2020 06:51:15 -0700
Subject: [PATCH] Add an ignore_scope option to dns.ipv6.inet_aton().

---
 dns/ipv6.py            | 13 ++++++++++++-
 tests/test_ntoaaton.py | 17 +++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/dns/ipv6.py b/dns/ipv6.py
index 1f703a67..43934cd4 100644
--- a/dns/ipv6.py
+++ b/dns/ipv6.py
@@ -96,11 +96,14 @@ _v4_ending = re.compile(br'(.*):(\d+\.\d+\.\d+\.\d+)$')
 _colon_colon_start = re.compile(br'::.*')
 _colon_colon_end = re.compile(br'.*::$')
 
-def inet_aton(text):
+def inet_aton(text, ignore_scope=False):
     """Convert an IPv6 address in text form to binary form.
 
     *text*, a ``text``, the IPv6 address in textual form.
 
+    *ignore_scope*, a ``bool``.  If ``True``, a scope will be ignored.
+    If ``False``, the default, it is an error for a scope to be present.
+
     Returns a ``bytes``.
     """
 
@@ -110,6 +113,14 @@ def inet_aton(text):
     if not isinstance(text, bytes):
         text = text.encode()
 
+    if ignore_scope:
+        parts = text.split(b'%')
+        l = len(parts)
+        if l == 2:
+            text = parts[0]
+        elif l > 2:
+            raise dns.exception.SyntaxError
+
     if text == b'::':
         text = b'0::'
     #
diff --git a/tests/test_ntoaaton.py b/tests/test_ntoaaton.py
index 2da0da6c..ba6cc30c 100644
--- a/tests/test_ntoaaton.py
+++ b/tests/test_ntoaaton.py
@@ -226,5 +226,22 @@ class NtoAAtoNTestCase(unittest.TestCase):
         self.assertFalse(dns.inet.is_multicast(t5))
         self.assertTrue(dns.inet.is_multicast(t6))
 
+    def test_ignore_scope(self):
+        t1 = 'fe80::1%lo0'
+        t2 = 'fe80::1'
+        self.assertEqual(aton6(t1, True), aton6(t2))
+
+    def test_do_not_ignore_scope(self):
+        def bad():
+            t1 = 'fe80::1%lo0'
+            aton6(t1)
+        self.assertRaises(dns.exception.SyntaxError, bad)
+
+    def test_multiple_scopes_bad(self):
+        def bad():
+            t1 = 'fe80::1%lo0%lo1'
+            aton6(t1, True)
+        self.assertRaises(dns.exception.SyntaxError, bad)
+
 if __name__ == '__main__':
     unittest.main()
-- 
2.47.3