From 1ad7ace6b7d551a28ddf3b0406b248f2891606a2 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Tue, 9 Aug 2022 13:28:39 +0800
Subject: [PATCH 1/9] Add conf new session tickets

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 include/mbedtls/mbedtls_config.h |  8 +++++++
 include/mbedtls/ssl.h            | 36 ++++++++++++++++++++++++++++----
 library/ssl_tls.c                | 13 ++++++++++++
 3 files changed, 53 insertions(+), 4 deletions(-)

diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index 687c5ef0ee..eea7f09808 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -1578,6 +1578,14 @@
  */
 #define MBEDTLS_SSL_TLS1_3_TICKET_NONCE_LENGTH 32
 
+/**
+ * \def MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS
+ *
+ * Default number of NewSessionTicket. This is not used in TLS 1.2.
+ *
+ */
+#define MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS 1
+
 /**
  * \def MBEDTLS_SSL_PROTO_DTLS
  *
diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 1e0220a6ac..0f008ea3e9 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -1329,9 +1329,17 @@ struct mbedtls_ssl_config
 #if defined(MBEDTLS_SSL_RENEGOTIATION)
     uint8_t MBEDTLS_PRIVATE(disable_renegotiation); /*!< disable renegotiation?     */
 #endif
-#if defined(MBEDTLS_SSL_SESSION_TICKETS)
-    uint8_t MBEDTLS_PRIVATE(session_tickets);   /*!< use session tickets?           */
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) && \
+    defined(MBEDTLS_SSL_CLI_C)
+    uint8_t MBEDTLS_PRIVATE(session_tickets);   /*!< use session tickets? */
 #endif
+
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) && \
+    defined(MBEDTLS_SSL_SRV_C) && \
+    defined(MBEDTLS_SSL_PROTO_TLS1_3)
+    uint16_t MBEDTLS_PRIVATE(new_session_tickets);   /*!< number of NewSessionTicket */
+#endif
+
 #if defined(MBEDTLS_SSL_SRV_C)
     uint8_t MBEDTLS_PRIVATE(cert_req_ca_list);  /*!< enable sending CA list in
                                                      Certificate Request messages? */
@@ -4109,7 +4117,8 @@ int mbedtls_ssl_conf_max_frag_len( mbedtls_ssl_config *conf, unsigned char mfl_c
 void mbedtls_ssl_conf_preference_order( mbedtls_ssl_config *conf, int order );
 #endif /* MBEDTLS_SSL_SRV_C */
 
-#if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_CLI_C)
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) && \
+    defined(MBEDTLS_SSL_CLI_C)
 /**
  * \brief          Enable / Disable session tickets (client only).
  *                 (Default: MBEDTLS_SSL_SESSION_TICKETS_ENABLED.)
@@ -4121,7 +4130,26 @@ void mbedtls_ssl_conf_preference_order( mbedtls_ssl_config *conf, int order );
  *                                         MBEDTLS_SSL_SESSION_TICKETS_DISABLED)
  */
 void mbedtls_ssl_conf_session_tickets( mbedtls_ssl_config *conf, int use_tickets );
-#endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_CLI_C */
+#endif /* MBEDTLS_SSL_SESSION_TICKETS &&
+          MBEDTLS_SSL_CLI_C */
+
+#if defined(MBEDTLS_SSL_SESSION_TICKETS) && \
+    defined(MBEDTLS_SSL_SRV_C) && \
+    defined(MBEDTLS_SSL_PROTO_TLS1_3)
+/**
+ * \brief          Number of NewSessionTicket message that sent by server.
+ *                 (Default: MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS)
+ *
+ *
+ * \param conf     SSL configuration
+ * \param num_tickets   Number of NewSessionTicket.
+ *
+ */
+void mbedtls_ssl_conf_new_session_tickets( mbedtls_ssl_config *conf,
+                                           uint16_t num_tickets );
+#endif /* MBEDTLS_SSL_SESSION_TICKETS &&
+          MBEDTLS_SSL_SRV_C &&
+          MBEDTLS_SSL_PROTO_TLS1_3*/
 
 #if defined(MBEDTLS_SSL_RENEGOTIATION)
 /**
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index af65e6d866..065b354d09 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -2611,6 +2611,15 @@ void mbedtls_ssl_conf_session_tickets( mbedtls_ssl_config *conf, int use_tickets
 #endif
 
 #if defined(MBEDTLS_SSL_SRV_C)
+
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+void mbedtls_ssl_conf_new_session_tickets( mbedtls_ssl_config *conf,
+                                           uint16_t num_tickets )
+{
+    conf->new_session_tickets = num_tickets;
+}
+#endif
+
 void mbedtls_ssl_conf_session_tickets_cb( mbedtls_ssl_config *conf,
         mbedtls_ssl_ticket_write_t *f_ticket_write,
         mbedtls_ssl_ticket_parse_t *f_ticket_parse,
@@ -4644,6 +4653,10 @@ int mbedtls_ssl_config_defaults( mbedtls_ssl_config *conf,
 #endif
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+#if defined(MBEDTLS_SSL_SRV_C)
+    mbedtls_ssl_conf_new_session_tickets(
+        conf, MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS );
+#endif
     /*
      * Allow all TLS 1.3 key exchange modes by default.
      */

From d4e7500a07ef25f1d2188322566125d9699b734c Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Tue, 9 Aug 2022 13:33:50 +0800
Subject: [PATCH 2/9] Enable multi session tickets on Server

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_misc.h         |  3 +++
 library/ssl_tls13_server.c | 19 +++++++++++++++++--
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 0b3ba90f74..2621d20055 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -624,6 +624,9 @@ struct mbedtls_ssl_handshake_params
 #if defined(MBEDTLS_KEY_EXCHANGE_SOME_PSK_ENABLED)
     uint8_t tls13_kex_modes; /*!< Key exchange modes supported by the client */
 #endif
+#if defined(MBEDTLS_SSL_SESSION_TICKETS)
+    int tls13_session_tickets;         /*!< number of session tickets */
+#endif
 #endif /* MBEDTLS_SSL_SRV_C */
 
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3 */
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index e185dc118c..780740897f 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -2617,7 +2617,8 @@ MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_tls13_write_new_session_ticket_coordinate( mbedtls_ssl_context *ssl )
 {
     /* Check whether the use of session tickets is enabled */
-    if( ssl->conf->f_ticket_write == NULL )
+    if( ssl->conf->f_ticket_write == NULL ||
+        ssl->handshake->tls13_session_tickets == 0 )
     {
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "new session ticket is not enabled" ) );
         return( SSL_NEW_SESSION_TICKET_SKIP );
@@ -2640,6 +2641,10 @@ static int ssl_tls13_prepare_new_session_ticket( mbedtls_ssl_context *ssl,
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> prepare NewSessionTicket msg" ) );
 
+    if( ssl->handshake->resume == 1 )
+        ssl->handshake->tls13_session_tickets = 0;
+    else
+        ssl->handshake->tls13_session_tickets--;
 #if defined(MBEDTLS_HAVE_TIME)
     session->start = mbedtls_time( NULL );
 #endif
@@ -2885,6 +2890,12 @@ int mbedtls_ssl_tls13_handshake_server_step( mbedtls_ssl_context *ssl )
         /* start state */
         case MBEDTLS_SSL_HELLO_REQUEST:
             mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_HELLO );
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_SESSION_TICKETS)
+            ssl->handshake->tls13_session_tickets =
+                ssl->conf->new_session_tickets ?
+                    ssl->conf->new_session_tickets :
+                    MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS;
+#endif
             ret = 0;
             break;
 
@@ -3002,7 +3013,11 @@ int mbedtls_ssl_tls13_handshake_server_step( mbedtls_ssl_context *ssl )
              * as part of ssl_prepare_handshake_step.
              */
             ret = 0;
-            mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_HANDSHAKE_OVER );
+
+            if( ssl->handshake->tls13_session_tickets == 0 )
+                mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_HANDSHAKE_OVER );
+            else
+                mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_NEW_SESSION_TICKET );
             break;
 
 #endif /* MBEDTLS_SSL_SESSION_TICKETS */

From 7a5130547893d7bf0d57af2dba1b5a74b4c2aaeb Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Tue, 9 Aug 2022 13:34:21 +0800
Subject: [PATCH 3/9] Add multi-session tickets test

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 programs/ssl/ssl_client2.c |  9 ++++++---
 programs/ssl/ssl_server2.c |  8 +++++---
 tests/ssl-opt.sh           | 26 ++++++++++++++++++++++----
 3 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/programs/ssl/ssl_client2.c b/programs/ssl/ssl_client2.c
index 050d51872b..3550c67bbf 100644
--- a/programs/ssl/ssl_client2.c
+++ b/programs/ssl/ssl_client2.c
@@ -1139,7 +1139,7 @@ int main( int argc, char *argv[] )
         else if( strcmp( p, "tickets" ) == 0 )
         {
             opt.tickets = atoi( q );
-            if( opt.tickets < 0 || opt.tickets > 2 )
+            if( opt.tickets < 0 )
                 goto usage;
         }
         else if( strcmp( p, "alpn" ) == 0 )
@@ -2668,6 +2668,9 @@ send_request:
      */
     if( opt.transport == MBEDTLS_SSL_TRANSPORT_STREAM )
     {
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_SESSION_TICKETS)
+        int ticket_id = 0;
+#endif
         do
         {
             len = sizeof( buf ) - 1;
@@ -2715,7 +2718,8 @@ send_request:
                     case MBEDTLS_ERR_SSL_RECEIVED_NEW_SESSION_TICKET:
                         /* We were waiting for application data but got
                          * a NewSessionTicket instead. */
-                        mbedtls_printf( " got new session ticket.\n" );
+                        mbedtls_printf( " got new session ticket ( %d ).\n",
+                                        ticket_id++ );
                         if( opt.reconnect != 0 )
                         {
                             mbedtls_printf("  . Saving session for reuse..." );
@@ -2749,7 +2753,6 @@ send_request:
                                                 (unsigned) session_data_len );
                             }
                         }
-
                         continue;
 #endif /* MBEDTLS_SSL_SESSION_TICKETS */
 
diff --git a/programs/ssl/ssl_server2.c b/programs/ssl/ssl_server2.c
index a1b29786d5..ff63fdd05c 100644
--- a/programs/ssl/ssl_server2.c
+++ b/programs/ssl/ssl_server2.c
@@ -1997,7 +1997,7 @@ int main( int argc, char *argv[] )
         else if( strcmp( p, "tickets" ) == 0 )
         {
             opt.tickets = atoi( q );
-            if( opt.tickets < 0 || opt.tickets > 1 )
+            if( opt.tickets < 0 )
                 goto usage;
         }
         else if( strcmp( p, "ticket_rotate" ) == 0 )
@@ -2915,7 +2915,7 @@ int main( int argc, char *argv[] )
 #endif
 
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
-    if( opt.tickets == MBEDTLS_SSL_SESSION_TICKETS_ENABLED )
+    if( opt.tickets != MBEDTLS_SSL_SESSION_TICKETS_DISABLED )
     {
         if( ( ret = mbedtls_ssl_ticket_setup( &ticket_ctx,
                         rng_get, &rng,
@@ -2930,7 +2930,9 @@ int main( int argc, char *argv[] )
                 mbedtls_ssl_ticket_write,
                 mbedtls_ssl_ticket_parse,
                 &ticket_ctx );
-
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+        mbedtls_ssl_conf_new_session_tickets( &conf, opt.tickets );
+#endif
         /* exercise manual ticket rotation (not required for typical use)
          * (used for external synchronization of session ticket encryption keys)
          */
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 84bcd3c095..f51d945519 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -12781,14 +12781,32 @@ run_test    "TLS 1.3: NewSessionTicket: Basic check, m->G" \
             -c "HTTP/1.0 200 OK" \
             -s "This is a resumed session"
 
+requires_openssl_tls1_3
+requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
+requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
+requires_config_enabled MBEDTLS_SSL_SRV_C
+requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
+# https://github.com/openssl/openssl/issues/10714
+# Until now, OpenSSL client does not support reconnect.
+skip_next_test
+run_test    "TLS 1.3: NewSessionTicket: Basic check, O->m" \
+            "$P_SRV debug_level=4 crt_file=data_files/server5.crt key_file=data_files/server5.key force_version=tls13 tickets=4" \
+            "$O_NEXT_CLI -msg -debug -tls1_3 -reconnect" \
+            0 \
+            -s "=> write NewSessionTicket msg" \
+            -s "server state: MBEDTLS_SSL_NEW_SESSION_TICKET" \
+            -s "server state: MBEDTLS_SSL_NEW_SESSION_TICKET_FLUSH"
+
 requires_gnutls_tls1_3
 requires_config_enabled MBEDTLS_SSL_PROTO_TLS1_3
 requires_config_enabled MBEDTLS_SSL_SESSION_TICKETS
 requires_config_enabled MBEDTLS_SSL_SRV_C
 requires_config_enabled MBEDTLS_DEBUG_C
+requires_config_enabled MBEDTLS_SSL_TLS1_3_COMPATIBILITY_MODE
 run_test    "TLS 1.3: NewSessionTicket: Basic check, G->m" \
-            "$P_SRV debug_level=4 crt_file=data_files/server5.crt key_file=data_files/server5.key force_version=tls13 tickets=1" \
-            "$G_NEXT_CLI localhost -d 4 --priority=NORMAL:-VERS-ALL:+VERS-TLS1.3:%DISABLE_TLS13_COMPAT_MODE -V -r" \
+            "$P_SRV debug_level=4 crt_file=data_files/server5.crt key_file=data_files/server5.key force_version=tls13 tickets=4" \
+            "$G_NEXT_CLI localhost -d 4 --priority=NORMAL:-VERS-ALL:+VERS-TLS1.3 -V -r" \
             0 \
             -c "Connecting again- trying to resume previous session" \
             -c "NEW SESSION TICKET (4) was received" \
@@ -12805,11 +12823,11 @@ requires_config_enabled MBEDTLS_SSL_SRV_C
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_DEBUG_C
 run_test    "TLS 1.3: NewSessionTicket: Basic check, m->m" \
-            "$P_SRV debug_level=4 crt_file=data_files/server5.crt key_file=data_files/server5.key force_version=tls13 tickets=1" \
+            "$P_SRV debug_level=4 crt_file=data_files/server5.crt key_file=data_files/server5.key force_version=tls13 tickets=4" \
             "$P_CLI debug_level=4 reco_mode=1 reconnect=1" \
             0 \
             -c "Protocol is TLSv1.3" \
-            -c "got new session ticket." \
+            -c "got new session ticket ( 3 )" \
             -c "Saving session for reuse... ok" \
             -c "Reconnecting with saved session" \
             -c "HTTP/1.0 200 OK"    \

From d0766eca58b2a53031e4d51ee32fb394309b9c25 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Thu, 22 Sep 2022 10:46:57 +0800
Subject: [PATCH 4/9] fix various issues

- Improve comments
- Align count variable name to `new_session_tickets_count`
- move tickets_count init to handshake init

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 include/mbedtls/ssl.h      |  6 +++---
 library/ssl_misc.h         |  2 +-
 library/ssl_tls.c          | 14 +++++++++++---
 library/ssl_tls13_server.c | 31 +++++++++++++++++++------------
 4 files changed, 34 insertions(+), 19 deletions(-)

diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 0f008ea3e9..1d5f4281fd 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -1337,7 +1337,7 @@ struct mbedtls_ssl_config
 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && \
     defined(MBEDTLS_SSL_SRV_C) && \
     defined(MBEDTLS_SSL_PROTO_TLS1_3)
-    uint16_t MBEDTLS_PRIVATE(new_session_tickets);   /*!< number of NewSessionTicket */
+    uint16_t MBEDTLS_PRIVATE(new_session_tickets_count);   /*!< number of NewSessionTicket */
 #endif
 
 #if defined(MBEDTLS_SSL_SRV_C)
@@ -4137,10 +4137,10 @@ void mbedtls_ssl_conf_session_tickets( mbedtls_ssl_config *conf, int use_tickets
     defined(MBEDTLS_SSL_SRV_C) && \
     defined(MBEDTLS_SSL_PROTO_TLS1_3)
 /**
- * \brief          Number of NewSessionTicket message that sent by server.
+ * \brief          Number of NewSessionTicket messages for the server to send
+ *                 after handshake completion.
  *                 (Default: MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS)
  *
- *
  * \param conf     SSL configuration
  * \param num_tickets   Number of NewSessionTicket.
  *
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 2621d20055..7e060d3348 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -625,7 +625,7 @@ struct mbedtls_ssl_handshake_params
     uint8_t tls13_kex_modes; /*!< Key exchange modes supported by the client */
 #endif
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
-    int tls13_session_tickets;         /*!< number of session tickets */
+    int new_session_tickets_count;         /*!< number of session tickets */
 #endif
 #endif /* MBEDTLS_SSL_SRV_C */
 
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 065b354d09..de6bae2833 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -674,6 +674,7 @@ static void ssl_handshake_params_init( mbedtls_ssl_handshake_params *handshake )
     !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     mbedtls_pk_init( &handshake->peer_pubkey );
 #endif
+
 }
 
 void mbedtls_ssl_transform_init( mbedtls_ssl_transform *transform )
@@ -763,6 +764,13 @@ static int ssl_handshake_init( mbedtls_ssl_context *ssl )
     mbedtls_ssl_transform_init( ssl->transform_negotiate );
     ssl_handshake_params_init( ssl->handshake );
 
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && \
+    defined(MBEDTLS_SSL_SRV_C) && \
+    defined(MBEDTLS_SSL_SESSION_TICKETS)
+    ssl->handshake->new_session_tickets_count =
+        ssl->conf->new_session_tickets_count ;
+#endif
+
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
     {
@@ -2612,11 +2620,11 @@ void mbedtls_ssl_conf_session_tickets( mbedtls_ssl_config *conf, int use_tickets
 
 #if defined(MBEDTLS_SSL_SRV_C)
 
-#if defined(MBEDTLS_SSL_PROTO_TLS1_3)
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_SESSION_TICKETS)
 void mbedtls_ssl_conf_new_session_tickets( mbedtls_ssl_config *conf,
                                            uint16_t num_tickets )
 {
-    conf->new_session_tickets = num_tickets;
+    conf->new_session_tickets_count = num_tickets;
 }
 #endif
 
@@ -4653,7 +4661,7 @@ int mbedtls_ssl_config_defaults( mbedtls_ssl_config *conf,
 #endif
 
 #if defined(MBEDTLS_SSL_PROTO_TLS1_3)
-#if defined(MBEDTLS_SSL_SRV_C)
+#if defined(MBEDTLS_SSL_SRV_C) && defined(MBEDTLS_SSL_SESSION_TICKETS)
     mbedtls_ssl_conf_new_session_tickets(
         conf, MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS );
 #endif
diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index 780740897f..40ac476673 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -2617,10 +2617,23 @@ MBEDTLS_CHECK_RETURN_CRITICAL
 static int ssl_tls13_write_new_session_ticket_coordinate( mbedtls_ssl_context *ssl )
 {
     /* Check whether the use of session tickets is enabled */
-    if( ssl->conf->f_ticket_write == NULL ||
-        ssl->handshake->tls13_session_tickets == 0 )
+    if( ssl->conf->f_ticket_write == NULL )
     {
-        MBEDTLS_SSL_DEBUG_MSG( 2, ( "new session ticket is not enabled" ) );
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "NewSessionTicket: disabled,"
+                                        " callback is not set" ) );
+        return( SSL_NEW_SESSION_TICKET_SKIP );
+    }
+    if( ssl->conf->new_session_tickets_count == 0 )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "NewSessionTicket: disabled,"
+                                        " configured count is zero" ) );
+        return( SSL_NEW_SESSION_TICKET_SKIP );
+    }
+
+    if( ssl->handshake->new_session_tickets_count == 0 )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "NewSessionTicket: all tickets have "
+                                        "been sent." ) );
         return( SSL_NEW_SESSION_TICKET_SKIP );
     }
 
@@ -2642,9 +2655,9 @@ static int ssl_tls13_prepare_new_session_ticket( mbedtls_ssl_context *ssl,
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> prepare NewSessionTicket msg" ) );
 
     if( ssl->handshake->resume == 1 )
-        ssl->handshake->tls13_session_tickets = 0;
+        ssl->handshake->new_session_tickets_count = 0;
     else
-        ssl->handshake->tls13_session_tickets--;
+        ssl->handshake->new_session_tickets_count--;
 #if defined(MBEDTLS_HAVE_TIME)
     session->start = mbedtls_time( NULL );
 #endif
@@ -2890,12 +2903,6 @@ int mbedtls_ssl_tls13_handshake_server_step( mbedtls_ssl_context *ssl )
         /* start state */
         case MBEDTLS_SSL_HELLO_REQUEST:
             mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_CLIENT_HELLO );
-#if defined(MBEDTLS_SSL_PROTO_TLS1_3) && defined(MBEDTLS_SSL_SESSION_TICKETS)
-            ssl->handshake->tls13_session_tickets =
-                ssl->conf->new_session_tickets ?
-                    ssl->conf->new_session_tickets :
-                    MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS;
-#endif
             ret = 0;
             break;
 
@@ -3014,7 +3021,7 @@ int mbedtls_ssl_tls13_handshake_server_step( mbedtls_ssl_context *ssl )
              */
             ret = 0;
 
-            if( ssl->handshake->tls13_session_tickets == 0 )
+            if( ssl->handshake->new_session_tickets_count == 0 )
                 mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_HANDSHAKE_OVER );
             else
                 mbedtls_ssl_handshake_set_state( ssl, MBEDTLS_SSL_NEW_SESSION_TICKET );

From b7e3fa7fbdd573f3f7f633da297a561eadac0fc5 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Thu, 22 Sep 2022 11:07:18 +0800
Subject: [PATCH 5/9] move count decrement after success sent

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_tls13_server.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index 40ac476673..e1e52cb457 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -2654,10 +2654,6 @@ static int ssl_tls13_prepare_new_session_ticket( mbedtls_ssl_context *ssl,
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> prepare NewSessionTicket msg" ) );
 
-    if( ssl->handshake->resume == 1 )
-        ssl->handshake->new_session_tickets_count = 0;
-    else
-        ssl->handshake->new_session_tickets_count--;
 #if defined(MBEDTLS_HAVE_TIME)
     session->start = mbedtls_time( NULL );
 #endif
@@ -2870,6 +2866,8 @@ static int ssl_tls13_write_new_session_ticket( mbedtls_ssl_context *ssl )
         MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg(
                                   ssl, buf_len, msg_len ) );
 
+        ssl->handshake->new_session_tickets_count--;
+
         mbedtls_ssl_handshake_set_state( ssl,
                                          MBEDTLS_SSL_NEW_SESSION_TICKET_FLUSH );
     }

From f3bdf9dd5125113d490fbcb3795d530f6979d08e Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Thu, 22 Sep 2022 23:30:49 +0800
Subject: [PATCH 6/9] fix various issues

- improve document about configuration item.
- format issue
- variable type issue.

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 include/mbedtls/mbedtls_config.h | 4 +++-
 library/ssl_misc.h               | 2 +-
 library/ssl_tls.c                | 1 -
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index eea7f09808..3df16777b0 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -1581,7 +1581,9 @@
 /**
  * \def MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS
  *
- * Default number of NewSessionTicket. This is not used in TLS 1.2.
+ * Default number of NewSessionTicket messages to be sent by a TLS 1.3 server
+ * after handshake completion. This is not used in TLS 1.2 and relevant only if
+ * the MBEDTLS_SSL_SESSION_TICKETS option is enabled.
  *
  */
 #define MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS 1
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 7e060d3348..e2546ffe97 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -625,7 +625,7 @@ struct mbedtls_ssl_handshake_params
     uint8_t tls13_kex_modes; /*!< Key exchange modes supported by the client */
 #endif
 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
-    int new_session_tickets_count;         /*!< number of session tickets */
+    uint16_t new_session_tickets_count;         /*!< number of session tickets */
 #endif
 #endif /* MBEDTLS_SSL_SRV_C */
 
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index de6bae2833..c9aea4857b 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -674,7 +674,6 @@ static void ssl_handshake_params_init( mbedtls_ssl_handshake_params *handshake )
     !defined(MBEDTLS_SSL_KEEP_PEER_CERTIFICATE)
     mbedtls_pk_init( &handshake->peer_pubkey );
 #endif
-
 }
 
 void mbedtls_ssl_transform_init( mbedtls_ssl_transform *transform )

From 359e65f78467962af579d25f869c632df3048eb4 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Thu, 22 Sep 2022 23:47:43 +0800
Subject: [PATCH 7/9] limit session ticket number when resumption

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 library/ssl_tls13_server.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/library/ssl_tls13_server.c b/library/ssl_tls13_server.c
index e1e52cb457..667e596e5c 100644
--- a/library/ssl_tls13_server.c
+++ b/library/ssl_tls13_server.c
@@ -2866,7 +2866,14 @@ static int ssl_tls13_write_new_session_ticket( mbedtls_ssl_context *ssl )
         MBEDTLS_SSL_PROC_CHK( mbedtls_ssl_finish_handshake_msg(
                                   ssl, buf_len, msg_len ) );
 
-        ssl->handshake->new_session_tickets_count--;
+        /* Limit session tickets count to one when resumption connection.
+         *
+         * See document of mbedtls_ssl_conf_new_session_tickets.
+         */
+        if( ssl->handshake->resume == 1 )
+            ssl->handshake->new_session_tickets_count = 0;
+        else
+            ssl->handshake->new_session_tickets_count--;
 
         mbedtls_ssl_handshake_set_state( ssl,
                                          MBEDTLS_SSL_NEW_SESSION_TICKET_FLUSH );

From 40b4a0138811b621553a29cde82015f5801dec94 Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Thu, 22 Sep 2022 23:48:38 +0800
Subject: [PATCH 8/9] Improve documents

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 include/mbedtls/ssl.h | 17 ++++++++++++-----
 1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 1d5f4281fd..ce2594991c 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -4137,12 +4137,19 @@ void mbedtls_ssl_conf_session_tickets( mbedtls_ssl_config *conf, int use_tickets
     defined(MBEDTLS_SSL_SRV_C) && \
     defined(MBEDTLS_SSL_PROTO_TLS1_3)
 /**
- * \brief          Number of NewSessionTicket messages for the server to send
- *                 after handshake completion.
- *                 (Default: MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS)
+* \brief    Number of NewSessionTicket messages for the server to send
+ *           after handshake completion.
+ * \note    The default value is
+ *          MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS.
+ * \note    In case of a session resumption, this setting only partially
+ *          apply. At most one ticket is sent in that case to just review the
+ *          pool of tickets of the client. The rationale is to avoid the
+ *          number of tickets on the server to become rapidly out of
+ *          control when the server has the same configuration for all its
+ *          connection instances.
  *
- * \param conf     SSL configuration
- * \param num_tickets   Number of NewSessionTicket.
+ * \param conf    SSL configuration
+ * \param num_tickets    Number of NewSessionTicket.
  *
  */
 void mbedtls_ssl_conf_new_session_tickets( mbedtls_ssl_config *conf,

From ba627bfd0d76dd91751cf178948953a149d4834d Mon Sep 17 00:00:00 2001
From: Jerry Yu <jerry.h.yu@arm.com>
Date: Fri, 23 Sep 2022 09:58:22 +0800
Subject: [PATCH 9/9] improve document about session tickets

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
---
 include/mbedtls/ssl.h | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index ce2594991c..0517e37ac5 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -4137,16 +4137,17 @@ void mbedtls_ssl_conf_session_tickets( mbedtls_ssl_config *conf, int use_tickets
     defined(MBEDTLS_SSL_SRV_C) && \
     defined(MBEDTLS_SSL_PROTO_TLS1_3)
 /**
-* \brief    Number of NewSessionTicket messages for the server to send
- *           after handshake completion.
+ * \brief   Number of NewSessionTicket messages for the server to send
+ *          after handshake completion.
+ *
  * \note    The default value is
- *          MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS.
- * \note    In case of a session resumption, this setting only partially
- *          apply. At most one ticket is sent in that case to just review the
- *          pool of tickets of the client. The rationale is to avoid the
- *          number of tickets on the server to become rapidly out of
- *          control when the server has the same configuration for all its
- *          connection instances.
+ *          \c MBEDTLS_SSL_TLS1_3_DEFAULT_NEW_SESSION_TICKETS.
+ *
+ * \note    In case of a session resumption, this setting only partially apply.
+ *          At most one ticket is sent in that case to just renew the pool of
+ *          tickets of the client. The rationale is to avoid the number of
+ *          tickets on the server to become rapidly out of control when the
+ *          server has the same configuration for all its connection instances.
  *
  * \param conf    SSL configuration
  * \param num_tickets    Number of NewSessionTicket.