feature for add tcp sack

components/lwip/Kconfig

@@ -400,6 +400,12 @@ menu "LWIP"
                 Disable this option to save some RAM during TCP sessions, at the expense
                 of increased retransmissions if segments arrive out of order.
 
+        config LWIP_TCP_SACK_OUT
+            bool "Support sending selective acknowledgements"
+            default n
+            help
+                TCP will support sending selective acknowledgements (SACKs).
+
         config LWIP_TCP_KEEP_CONNECTION_WHEN_IP_CHANGES
             bool "Keep TCP connections when IP changed"
             default n

components/lwip/port/esp32/include/lwipopts.h

@@ -311,6 +311,11 @@
  */
 #define TCP_QUEUE_OOSEQ                 CONFIG_LWIP_TCP_QUEUE_OOSEQ
 
+/**
+ * LWIP_TCP_SACK_OUT==1: TCP will support sending selective acknowledgements (SACKs).
+ */
+#define LWIP_TCP_SACK_OUT               CONFIG_LWIP_TCP_SACK_OUT
+
 /**
  * ESP_TCP_KEEP_CONNECTION_WHEN_IP_CHANGES==1: Keep TCP connection when IP changed
  * scenario happens: 192.168.0.2 -> 0.0.0.0 -> 192.168.0.2 or 192.168.0.2 -> 0.0.0.0