Check presence of DTLS timers only once
Mbed TLS requires users of DTLS to configure timer callbacks
needed to implement the wait-and-retransmit logic of DTLS.
Previously, the presence of these timer callbacks was checked
at every invocation of `mbedtls_ssl_fetch_input()`, so lowest
layer of the messaging stack interfacing with the underlying
transport.
This commit removes this recurring check and instead checks the
presence of timers once at the beginning of the handshake.
The main rationale for this change is that it is a step towards
separating the various layers of the messaging stack more cleanly:
datagram layer, record layer, message layer, retransmission layer.
Signed-off-by: Hanno Becker <hanno.becker@arm.com>
diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index 981d94e..bdf882d 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -2018,14 +2018,6 @@
{
uint32_t timeout;
- /* Just to be sure */
- if( ssl->f_set_timer == NULL || ssl->f_get_timer == NULL )
- {
- MBEDTLS_SSL_DEBUG_MSG( 1, ( "You must use "
- "mbedtls_ssl_set_timer_cb() for DTLS" ) );
- return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
- }
-
/*
* The point is, we need to always read a full datagram at once, so we
* sometimes read more then requested, and handle the additional data.
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 7062d53..34953f2 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -5682,11 +5682,24 @@
{
int ret = 0;
+ /* Sanity checks */
+
if( ssl == NULL || ssl->conf == NULL )
return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+ if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+ ( ssl->f_set_timer == NULL || ssl->f_get_timer == NULL ) )
+ {
+ MBEDTLS_SSL_DEBUG_MSG( 1, ( "You must use "
+ "mbedtls_ssl_set_timer_cb() for DTLS" ) );
+ return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
+ }
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> handshake" ) );
+ /* Main handshake loop */
while( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER )
{
ret = mbedtls_ssl_handshake_step( ssl );