add supported versions extension
@@ -400,15 +400,49 @@ static int ssl_client_hello_write_partial( mbedtls_ssl_context* ssl,
return( 0 );
}
+/*
+ * ssl_write_supported_versions_ext():
+ *
+ * struct {
+ * ProtocolVersion versions<2..254>;
+ * } SupportedVersions;
+ */
static void ssl_write_supported_versions_ext( mbedtls_ssl_context *ssl,
unsigned char* buf,
unsigned char* end,
size_t* olen )
{
- ((void) ssl);
- ((void) buf);
- ((void) end);
- ((void) olen);
+ unsigned char *p = buf;
+
+ *olen = 0;
+
+ MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, adding supported version extension" ) );
+
+ if( end < p || (size_t)( end - p ) < 7 )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small" ) );
+ return;
+ }
+
+ *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS >> 8 ) & 0xFF );
+ *p++ = (unsigned char)( ( MBEDTLS_TLS_EXT_SUPPORTED_VERSIONS ) & 0xFF );
+
+ /* total length */
+ *p++ = 0x00;
+ *p++ = 3;
+
+ /* length of next field */
+ *p++ = 0x2;
+
+ /* This implementation only supports a single TLS version, and only
+ * advertises a single value.
+ */
+ mbedtls_ssl_write_version( ssl->conf->max_major_ver, ssl->conf->max_minor_ver,
+ ssl->conf->transport, p );
+
+ MBEDTLS_SSL_DEBUG_MSG( 3, ( "supported version: [%d:%d]", ssl->conf->max_major_ver, ssl->conf->max_minor_ver ) );
+
+ *olen = 7;
}
#if defined(MBEDTLS_KEY_EXCHANGE_WITH_CERT_ENABLED)
