swanctl: Document the remote ca_id option for identity based CA constraints

diff --git a/src/swanctl/swanctl.opt b/src/swanctl/swanctl.opt
index f7801b3c3959be679ebd9c20f55fe01dec784a5e..0ae9d457905d44655e5539c61524a4711ed1cdb4 100644 (file)
--- a/src/swanctl/swanctl.opt
+++ b/src/swanctl/swanctl.opt
@@ -593,6 +593,16 @@ connections.<conn>.remote<suffix>.cacert<suffix>.slot =
 connections.<conn>.remote<suffix>.cacert<suffix>.module =
        Optional PKCS#11 module name.
 
+connections.<conn>.remote<suffix>.ca_id =
+       Identity in CA certificate to accept for authentication.
+
+       The specified identity must be contained in one (intermediate) CA
+       of the remote peer trustchain, either as subject or as subjectAltName.
+       This has the same effect as specifying _cacerts_ to force clients under
+       a CA to specific connections; it does not require the CA certificate to
+       be available locally, and can be received from the peer during the
+       IKE exchange.
+
 connections.<conn>.remote<suffix>.pubkeys =
        Comma separated list of raw public keys to accept for authentication.