feat(lwip): make tcp fast timer to 125ms and make rto to 250ms

components/lwip/lwip/src/core/tcp.c

@@ -108,8 +108,13 @@ static u16_t tcp_port = TCP_LOCAL_PORT_RANGE_START;
 
 /* Incremented every coarse grained timer shot (typically every 500 ms). */
 u32_t tcp_ticks;
+#if TCP_HIGH_SPEED_RETRANSMISSION
+static const u8_t tcp_backoff[13] =
+    { 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7};
+#else
 static const u8_t tcp_backoff[13] =
     { 1, 2, 3, 4, 5, 6, 7, 7, 7, 7, 7, 7, 7};
+#endif
  /* Times per slowtmr hits */
 static const u8_t tcp_persist_backoff[7] = { 3, 6, 12, 24, 48, 96, 120 };
 

components/lwip/lwip/src/include/lwip/priv/tcp_priv.h

@@ -114,7 +114,11 @@ err_t            tcp_process_refused_data(struct tcp_pcb *pcb);
 #define TCP_SEQ_BETWEEN(a,b,c) (TCP_SEQ_GEQ(a,b) && TCP_SEQ_LEQ(a,c))
 
 #ifndef TCP_TMR_INTERVAL
+#if TCP_HIGH_SPEED_RETRANSMISSION
+#define TCP_TMR_INTERVAL       125  /* The TCP timer interval in milliseconds. */
+#else
 #define TCP_TMR_INTERVAL       250  /* The TCP timer interval in milliseconds. */
+#endif
 #endif /* TCP_TMR_INTERVAL */
 
 #ifndef TCP_FAST_INTERVAL

components/lwip/port/esp8266/include/lwipopts.h

@@ -62,6 +62,7 @@
 
 //#define SOCKETS_TCP_TRACE
 
+#define TCP_HIGH_SPEED_RETRANSMISSION CONFIG_TCP_HIGH_SPEED_RETRANSMISSION
 
  /*
    ------------------------------------