Merge pull request #128 from MisterHW/keep-alive

set keep-alive defaults for new connections
j123b567 · Nov 9, 2021 · 224f7ce · 224f7ce
2 parents 77670c4 + 42841c3
commit 224f7ce
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diff --git a/examples/test-LwIP-netconn/scpi_server.c b/examples/test-LwIP-netconn/scpi_server.c
@@ -246,6 +246,10 @@ static int processIoListen(scpi_t * context, user_data_t * user_data) {
         } else {
             /* connection established */
             SCPI_Event_DeviceConnected(context, newconn);
+            ip_set_option(newconn->pcb.tcp, SOF_KEEPALIVE);
+            newconn->pcb.tcp->keep_idle   = SCPI_KEEP_IDLE;  // Override TCP_KEEPIDLE_DEFAULT  for this connection.
+            newconn->pcb.tcp->keep_intvl  = SCPI_KEEP_INTVL; // Override TCP_KEEPINTVL_DEFAULT for this connection.
+            newconn->pcb.tcp->keep_cnt    = SCPI_KEEP_CNT;   // Override TCP_KEEPCNT_DEFAULT   for this connection.
             user_data->io = newconn;
         }
     }
@@ -263,6 +267,10 @@ static int processSrqIoListen(scpi_t * context, user_data_t * user_data) {
         } else {
             /* control connection established */
             SCPI_Event_ControlConnected(context, newconn);
+            ip_set_option(newconn->pcb.tcp, SOF_KEEPALIVE);
+            newconn->pcb.tcp->keep_idle   = SCPI_KEEP_IDLE;  // Override TCP_KEEPIDLE_DEFAULT  for this connection.
+            newconn->pcb.tcp->keep_intvl  = SCPI_KEEP_INTVL; // Override TCP_KEEPINTVL_DEFAULT for this connection.
+            newconn->pcb.tcp->keep_cnt    = SCPI_KEEP_CNT;   // Override TCP_KEEPCNT_DEFAULT   for this connection.
             user_data->control_io = newconn;
         }
     }

diff --git a/examples/test-LwIP-netconn/scpi_server.h b/examples/test-LwIP-netconn/scpi_server.h
@@ -32,6 +32,10 @@
 extern "C" {
 #endif
 
+#define SCPI_KEEP_IDLE    2000 // (ms) keepalive quiet time after last TCP packet
+#define SCPI_KEEP_INTVL   1000 // (ms) keepalive repeat interval
+#define SCPI_KEEP_CNT        4 // Retry count before terminating connection (SCPI_KEEP_INTVL * SCPI_KEEP_INTVL (ms)).
+
 #define SCPI_DEVICE_PORT  5025 // scpi-raw standard port
 #define SCPI_CONTROL_PORT 5026 // libscpi control port (not part of the standard)