From: Bob Halley <halley@dnspython.org>
Date: Tue, 16 Jun 2020 00:19:18 +0000 (-0700)
Subject: avoid getaddrinfo() when we can
X-Git-Tag: v2.0.0rc1~100
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a867ef1c8af00734138c8e72321782ef3a798013;p=thirdparty%2Fdnspython.git

avoid getaddrinfo() when we can
---

diff --git a/dns/inet.py b/dns/inet.py
index 71782ac3..d434948f 100644
--- a/dns/inet.py
+++ b/dns/inet.py
@@ -157,8 +157,20 @@ def low_level_address_tuple(high_tuple, af=None):
     if af == AF_INET:
         return (address, port)
     elif af == AF_INET6:
-        ai_flags = socket.AI_NUMERICHOST
-        ((*_, tup), *_) = socket.getaddrinfo(address, port, flags=ai_flags)
-        return tup
+        i = address.find('%')
+        if i < 0:
+            # no scope, shortcut!
+            return (address, port, 0, 0)
+        # try to avoid getaddrinfo()
+        addrpart = address[:i]
+        scope = address[i+1:]
+        if scope.isdigit():
+            return (addrpart, port, 0, int(scope))
+        try:
+            return (addrpart, port, 0, socket.if_nametoindex(scope))
+        except AttributeError:
+            ai_flags = socket.AI_NUMERICHOST
+            ((*_, tup), *_) = socket.getaddrinfo(address, port, flags=ai_flags)
+            return tup
     else:
         raise NotImplementedError(f'unknown address family {af}')