Added chacha20-poly1305 as a DTLS ciphersuite for gnutls

Signed-off-by: Nikos Mavrogiannopoulos <nmav@redhat.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

dtls.c

@@ -450,6 +450,9 @@ void append_dtls_ciphers(struct openconnect_info *vpninfo, struct oc_text_buf *b
 #if GNUTLS_VERSION_NUMBER < 0x030200
 # define GNUTLS_DTLS1_2 202
 #endif
+#if GNUTLS_VERSION_NUMBER < 0x030400
+# define GNUTLS_CIPHER_CHACHA20_POLY1305 23
+#endif
 
 struct {
 	const char *name;
@@ -469,6 +472,8 @@ struct {
 	  "NONE:+VERS-DTLS1.2:+COMP-NULL:+AES-128-GCM:+AEAD:+RSA:%COMPAT:+SIGN-ALL", "3.2.7" },
 	{ "OC-DTLS1_2-AES256-GCM", GNUTLS_DTLS1_2, GNUTLS_CIPHER_AES_256_GCM, GNUTLS_MAC_AEAD,
 	  "NONE:+VERS-DTLS1.2:+COMP-NULL:+AES-256-GCM:+AEAD:+RSA:%COMPAT:+SIGN-ALL", "3.2.7" },
+	{ "OC-DTLS1_2-CHACHA20-POLY1305", GNUTLS_DTLS1_2, GNUTLS_CIPHER_CHACHA20_POLY1305, GNUTLS_MAC_AEAD,
+	  "NONE:+VERS-DTLS1.2:+COMP-NULL:+CHACHA20-POLY1305:+AEAD:+RSA:%COMPAT:+SIGN-ALL", "3.4.0" },
 };
 
 #if GNUTLS_VERSION_NUMBER < 0x030009