From 1cc0a303f8cf1664a6f857ae400c973c7fd37aa4 Mon Sep 17 00:00:00 2001
From: DerEnderKeks <derenderkeks@gmail.com>
Date: Sat, 24 Feb 2024 18:53:15 +0100
Subject: [PATCH] fix: use dual-stack socket instead of IPv4-only

By using an INET6 socket with IPV6_V6ONLY disabled, legacy IPv4 can still be reached. To connect to v4 IPs, the addresses are mapped to IPv6. IPv6 addresses are only used when a hostname resolves to one and the system has a non-local IPv6 available.
---
 pychromecast/socket_client.py | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/pychromecast/socket_client.py b/pychromecast/socket_client.py
index db14e0511..595a71076 100644
--- a/pychromecast/socket_client.py
+++ b/pychromecast/socket_client.py
@@ -352,7 +352,16 @@ def mdns_backoff(
                         self.host,
                         self.port,
                     )
-                    self.socket.connect((self.host, self.port))
+
+                    mapped_host = socket.getaddrinfo(
+                        self.host,
+                        self.port,
+                        socket.AF_INET6,
+                        socket.SOCK_STREAM,
+                        flags=(socket.AI_ADDRCONFIG | socket.AI_V4MAPPED)
+                    )[0][4]
+
+                    self.socket.connect(mapped_host)
                     context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT)
                     context.check_hostname = False
                     context.verify_mode = ssl.CERT_NONE
@@ -1135,7 +1144,8 @@ def new_socket() -> socket.socket:
     Try to set SO_REUSEPORT for BSD-flavored systems if it's an option.
     Catches errors if not.
     """
-    new_sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    new_sock = socket.socket(socket.AF_INET6, socket.SOCK_STREAM)
+    new_sock.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, 0)
     new_sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
 
     try: