fix(proxy): do not warn about requests to a configured remote CDM

docs/guide/proxies-and-vpn.md

@@ -198,6 +198,8 @@ file and line, to the service maintainer.
 
 A request to your own machine or to your local network gives no warning. This includes a
 private IP address such as `192.168.1.50`, and a `.local`, `.lan` or `.home.arpa` host name.
+A request to the `host` of a remote CDM in `remote_cdm` also gives no warning. The CDM API
+sees your own IP, but the service does not.
 
 A `socks5://` proxy makes the DNS lookup of each host on your machine and gives no warning.
 Use `socks5h://` to make the proxy do the DNS lookups too.

tests/core/test_run_proxy.py

@@ -84,6 +84,16 @@ def test_proxy_and_local_hosts_do_not_warn(caplog, host):
     assert leaks(caplog) == []
 
 
+def test_remote_cdm_host_does_not_warn(caplog, monkeypatch):
+    """A service calls its remote CDM itself, so no core frame ends the walk; the CDM API is not the service."""
+    from unshackle.core.config import config
+
+    monkeypatch.setattr(config, "remote_cdm", [{"name": "pr", "host": "https://cdm.example/playready"}])
+    with caplog.at_level(logging.WARNING):
+        lookup("cdm.example")
+    assert leaks(caplog) == []
+
+
 @pytest.mark.parametrize("host", ["8.8.8.8", "2606:4700:4700::1111", "api.example"])
 def test_public_hosts_warn(caplog, host):
     with caplog.at_level(logging.WARNING):

unshackle/core/utils/run_proxy.py

@@ -134,6 +134,13 @@ def fallback_session() -> requests.Session:
     return session
 
 
+def cdm_hosts() -> set[str]:
+    """The hosts of the remote CDMs in the config: a CDM API of the user, which a service calls direct."""
+    from unshackle.core.config import config
+
+    return {hostname(str(x.get("host") or x.get("Host") or "")) for x in config.remote_cdm}
+
+
 def is_local(host: str) -> bool:
     """True for this machine and the local network, which never see the internet IP of the user."""
     if host in ("localhost", "localhost.", "localhost.localdomain"):
@@ -177,7 +184,7 @@ def check(host: Any, frame: Optional[FrameType]) -> None:
     if isinstance(host, bytes):
         host = host.decode(errors="replace")
     host = str(host or "").lower().strip("[]")
-    if not host or is_local(host) or host in proxy_hosts:
+    if not host or is_local(host) or host in proxy_hosts or host in cdm_hosts():
         return
     found = find_service(frame, through_core=False)
     if not found: