Merge pull request #9183 from SeppoTakalo/lwip_tcp_timeout

 Allow LwIP TCP retransmissions to be configured and tune those smaller.

Author: 0xc0170

features/lwipstack/lwipopts.h

@@ -159,6 +159,14 @@
 #define TCP_WND                     MBED_CONF_LWIP_TCP_WND
 #endif
 
+#ifdef MBED_CONF_LWIP_TCP_MAXRTX
+#define TCP_MAXRTX                  MBED_CONF_LWIP_TCP_MAXRTX
+#endif
+
+#ifdef MBED_CONF_LWIP_TCP_SYNMAXRTX
+#define TCP_SYNMAXRTX               MBED_CONF_LWIP_TCP_SYNMAXRTX
+#endif
+
 // Number of pool pbufs.
 // Each requires 684 bytes of RAM (if MSS=536 and PBUF_POOL_BUFSIZE defaulting to be based on MSS)
 #ifdef MBED_CONF_LWIP_PBUF_POOL_SIZE

features/lwipstack/mbed_lib.json

@@ -88,6 +88,14 @@
             "help": "TCP sender buffer space (bytes). Current default (used if null here) is set to (4 * TCP_MSS) in opt.h, unless overridden by target Ethernet drivers.",
             "value": null
         },
+        "tcp-maxrtx": {
+            "help": "Maximum number of retransmissions of data segments.",
+            "value": 6
+        },
+        "tcp-synmaxrtx": {
+            "help": "Maximum number of retransmissions of SYN segments. Current default (used if null here) is set to 6 in opt.h",
+            "value": null
+        },
         "pbuf-pool-size": {
             "help": "Number of pbufs in pool - usually used for received packets, so this determines how much data can be buffered between reception and the application reading. If a driver uses PBUF_RAM for reception, less pool may be needed. Current default (used if null here) is set to 5 in lwipopts.h, unless overridden by target Ethernet drivers.",
             "value": null
@@ -125,7 +133,7 @@
             "mem-size": 25600
         },
         "Freescale": {
-            "mem-size": 36560
+            "mem-size": 16384
         },
         "LPC1768": {
             "mem-size": 16362

features/netsocket/emac-drivers/TARGET_Freescale_EMAC/mbed_lib.json

@@ -1,7 +1,7 @@
 {
     "name": "kinetis-emac",
     "config": {
-        "rx-ring-len": 16,
-        "tx-ring-len": 8
+        "rx-ring-len": 2,
+        "tx-ring-len": 1
     }
 }