session tls: improve app transports tx scheduling

Type: improvement

- allow apps to request rescheduling of tx events via
SESSION_F_CUSTOM_TX flag
- limit max burst per session custom tx dispatch

In tls
- use the new infra to reschedule tx events
- use max burst bytes as upper limit to number of bytes to be encrypted

Signed-off-by: Florin Coras <fcoras@cisco.com>
Change-Id: I544a5a3337af7ebdff3406b776adf30cf96ebf3c

1 files changed, 5 insertions, 4 deletions

diff --git a/src/plugins/tlsmbedtls/tls_mbedtls.c b/src/plugins/tlsmbedtls/tls_mbedtls.c
index 7b722faf822..8ac736ae6f3 100644
--- a/src/plugins/tlsmbedtls/tls_mbedtls.c
+++ b/src/plugins/tlsmbedtls/tls_mbedtls.c
@@ -431,7 +431,7 @@ mbedtls_ctx_handshake_rx (tls_ctx_t * ctx)
 }
 
 static int
-mbedtls_ctx_write (tls_ctx_t * ctx, session_t * app_session)
+mbedtls_ctx_write (tls_ctx_t * ctx, session_t * app_session, u32 max_write)
 {
   mbedtls_ctx_t *mc = (mbedtls_ctx_t *) ctx;
   u8 thread_index = ctx->c_thread_index;
@@ -446,13 +446,14 @@ mbedtls_ctx_write (tls_ctx_t * ctx, session_t * app_session)
   if (!deq_max)
     return 0;
 
+  deq_max = clib_min (deq_max, max_write);
   tls_session = session_get_from_handle (ctx->tls_session_handle);
   enq_max = svm_fifo_max_enqueue_prod (tls_session->tx_fifo);
   deq_now = clib_min (deq_max, TLS_CHUNK_SIZE);
 
   if (PREDICT_FALSE (enq_max == 0))
     {
-      tls_add_vpp_q_builtin_tx_evt (app_session);
+      app_session->flags |= SESSION_F_CUSTOM_TX;
       return 0;
     }
 
@@ -462,7 +463,7 @@ mbedtls_ctx_write (tls_ctx_t * ctx, session_t * app_session)
   wrote = mbedtls_ssl_write (&mc->ssl, mm->tx_bufs[thread_index], deq_now);
   if (wrote <= 0)
     {
-      tls_add_vpp_q_builtin_tx_evt (app_session);
+      app_session->flags |= SESSION_F_CUSTOM_TX;
       return 0;
     }
 
@@ -471,7 +472,7 @@ mbedtls_ctx_write (tls_ctx_t * ctx, session_t * app_session)
   tls_add_vpp_q_tx_evt (tls_session);
 
   if (deq_now < deq_max)
-    tls_add_vpp_q_builtin_tx_evt (app_session);
+    app_session->flags |= SESSION_F_CUSTOM_TX;
 
   return 0;
 }