From 9df5203d3d2787033c99a5054121ccfcd7c1c9c5 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sat, 18 Sep 2021 23:22:39 -1000
Subject: [PATCH] Simplify the can_send_to check

- There is no need to call can_send_to when we derive the target

- can_send_to was converting the addr string into an ipaddress object
  to check if it was IPv4 or IPv6. Since this all happens internally there
  was no need for the additional validation and check. We can use a must
  more simple test.
---
 zeroconf/__init__.py   |  1 -
 zeroconf/_core.py      |  9 +++++----
 zeroconf/_utils/net.py | 10 +++++++---
 3 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/zeroconf/__init__.py b/zeroconf/__init__.py
index 055d0439e..5c04eb26e 100644
--- a/zeroconf/__init__.py
+++ b/zeroconf/__init__.py
@@ -67,7 +67,6 @@
 from ._utils.name import service_type_name  # noqa # import needed for backwards compat
 from ._utils.net import (  # noqa # import needed for backwards compat
     add_multicast_member,
-    can_send_to,
     autodetect_ip_version,
     create_sockets,
     get_all_addresses_v6,
diff --git a/zeroconf/_core.py b/zeroconf/_core.py
index 15852ffb2..74b1828f0 100644
--- a/zeroconf/_core.py
+++ b/zeroconf/_core.py
@@ -836,12 +836,13 @@ def _async_send_transport(
         v6_flow_scope: Union[Tuple[()], Tuple[int, int]] = (),
     ) -> None:
         s = transport.get_extra_info('socket')
+        ipv6_socket = s.family == socket.AF_INET6
         if addr is None:
-            real_addr = _MDNS_ADDR6 if s.family == socket.AF_INET6 else _MDNS_ADDR
+            real_addr = _MDNS_ADDR6 if ipv6_socket else _MDNS_ADDR
         else:
             real_addr = addr
-        if not can_send_to(s, real_addr):
-            return
+            if not can_send_to(ipv6_socket, real_addr):
+                return
         log.debug(
             'Sending to (%s, %d) via [socket %s (%s)] (%d bytes #%d) %r as %r...',
             real_addr,
@@ -855,7 +856,7 @@ def _async_send_transport(
         )
         # Get flowinfo and scopeid for the IPV6 socket to create a complete IPv6
         # address tuple: https://docs.python.org/3.6/library/socket.html#socket-families
-        if s.family == socket.AF_INET6 and not v6_flow_scope:
+        if ipv6_socket and not v6_flow_scope:
             _, _, sock_flowinfo, sock_scopeid = s.getsockname()
             v6_flow_scope = (sock_flowinfo, sock_scopeid)
         transport.sendto(packet, (real_addr, port or _MDNS_PORT, *v6_flow_scope))
diff --git a/zeroconf/_utils/net.py b/zeroconf/_utils/net.py
index bfae9db46..c53ec9786 100644
--- a/zeroconf/_utils/net.py
+++ b/zeroconf/_utils/net.py
@@ -379,9 +379,13 @@ def get_errno(e: Exception) -> int:
     return cast(int, e.args[0])
 
 
-def can_send_to(sock: socket.socket, address: str) -> bool:
-    addr = ipaddress.ip_address(address)
-    return cast(bool, addr.version == 6 if sock.family == socket.AF_INET6 else addr.version == 4)
+def can_send_to(ipv6_socket: bool, address: str) -> bool:
+    """Check if the address type matches the socket type.
+
+    This function does not validate if the address is a valid
+    ipv6 or ipv4 address.
+    """
+    return ":" in address if ipv6_socket else ":" not in address
 
 
 def autodetect_ip_version(interfaces: InterfacesType) -> IPVersion: