http: fix sending error responses to rejected requests by server apps

Plugins such as http_static sometimes reject requests without reading
all of the body. http_static in that case sends an error response and
closes the connection. But the error response cannot go out due to the
connection state being HTTP_REQ_STATE_TRANSPORT_IO_MORE_DATA.
With this change, we make http_app_tx_callback give a response like
that special treatment, allowing it to go out.

Type: fix
Change-Id: I72ae74b869183f5d5921837f6ac9c52f0efc7598
Signed-off-by: Semir Sionek <ssionek@cisco.com>

1 files changed, 18 insertions, 7 deletions

diff --git a/src/plugins/http/http.c b/src/plugins/http/http.c
index 5a0c6541598..c33c85a303e 100644
--- a/src/plugins/http/http.c
+++ b/src/plugins/http/http.c
@@ -2467,13 +2467,24 @@ http_app_tx_callback (void *session, transport_send_params_t *sp)
 
   if (!http_req_state_is_tx_valid (hc))
     {
-      clib_warning ("hc [%u]%x invalid tx state: http req state "
-		    "'%U', session state '%U'",
-		    as->thread_index, as->connection_index,
-		    format_http_req_state, hc->req.state,
-		    format_http_conn_state, hc);
-      svm_fifo_dequeue_drop_all (as->tx_fifo);
-      return 0;
+      /* Sometimes the server apps can send the response earlier
+       * than expected (e.g when rejecting a bad request)*/
+      if (hc->req.state == HTTP_REQ_STATE_TRANSPORT_IO_MORE_DATA &&
+	  hc->is_server)
+	{
+	  svm_fifo_dequeue_drop_all (as->rx_fifo);
+	  hc->req.state = HTTP_REQ_STATE_WAIT_APP_REPLY;
+	}
+      else
+	{
+	  clib_warning ("hc [%u]%x invalid tx state: http req state "
+			"'%U', session state '%U'",
+			as->thread_index, as->connection_index,
+			format_http_req_state, hc->req.state,
+			format_http_conn_state, hc);
+	  svm_fifo_dequeue_drop_all (as->tx_fifo);
+	  return 0;
+	}
     }
 
   HTTP_DBG (1, "run state machine");