add and send IV_PROTO_DNS_OPTION_V2 flag

Incompatible changes to the --dns server address and --dns server
exclude-domains options were introduced after the code for handling them
was released. Add and send a new IV_PROTO flag, so servers which act on
the flags set can differentiate between clients which have implemented
--dns and those which just support the new option. This enables them to
decide which variant of options to send to the client.

Change-Id: I975057c20c1457ef88111f8d142ca3fd2039d5ff
Signed-off-by: Heiko Hund <heiko@ist.eigentlich.net>
Acked-by: Arne Schwabe <arne-openvpn@rfc2549.org>
Message-Id: <20240725112248.21075-1-gert@greenie.muc.de>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg28970.html
Signed-off-by: Gert Doering <gert@greenie.muc.de>

diff --git a/src/openvpn/ssl.c b/src/openvpn/ssl.c
index e0e9591d3a54be2c29b4883f19fcd4898cb51b0b..14c38cfba62c75dd84cec6faea903f17b5bbaf20 100644 (file)
--- a/src/openvpn/ssl.c
+++ b/src/openvpn/ssl.c
@@ -1900,8 +1900,8 @@ push_peer_info(struct buffer *buf, struct tls_session *session)
         /* support for P_DATA_V2 */
         int iv_proto = IV_PROTO_DATA_V2;
 
-        /* support for the --dns option */
-        iv_proto |= IV_PROTO_DNS_OPTION;
+        /* support for the latest --dns option */
+        iv_proto |= IV_PROTO_DNS_OPTION_V2;
 
         /* support for exit notify via control channel */
         iv_proto |= IV_PROTO_CC_EXIT_NOTIFY;

diff --git a/src/openvpn/ssl.h b/src/openvpn/ssl.h
index 1a4504822579818397adcb54f6532b1a07fcb56a..6c2bfc322cdda17aa1fe8613cbdd902002f9a15a 100644 (file)
--- a/src/openvpn/ssl.h
+++ b/src/openvpn/ssl.h
@@ -94,7 +94,7 @@
  * result. */
 #define IV_PROTO_NCP_P2P         (1<<5)
 
-/** Supports the --dns option introduced in version 2.6 */
+/** Supports the --dns option introduced in version 2.6. Not sent anymore. */
 #define IV_PROTO_DNS_OPTION      (1<<6)
 
 /** Support for explicit exit notify via control channel
@@ -107,6 +107,9 @@
 /** Support to dynamic tls-crypt (renegotiation with TLS-EKM derived tls-crypt key) */
 #define IV_PROTO_DYN_TLS_CRYPT   (1<<9)
 
+/** Supports the --dns option after all the incompatible changes */
+#define IV_PROTO_DNS_OPTION_V2   (1<<11)
+
 /* Default field in X509 to be username */
 #define X509_USERNAME_FIELD_DEFAULT "CN"