From 4df05993742ac04f9d1ec3f3ae429816da8d6955 Mon Sep 17 00:00:00 2001
From: Mark Webb-Johnson <mark@webb-johnson.net>
Date: Thu, 1 Mar 2018 08:48:06 +0800
Subject: [PATCH] Extension to lwip sntp to provide a weak callback notifying
 us the time has been set by sntp

---
 components/lwip/apps/sntp/sntp.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/components/lwip/apps/sntp/sntp.c b/components/lwip/apps/sntp/sntp.c
index 6bee032fc..a9e5833ae 100644
--- a/components/lwip/apps/sntp/sntp.c
+++ b/components/lwip/apps/sntp/sntp.c
@@ -198,6 +198,19 @@ static ip_addr_t sntp_last_server_address;
 static u32_t sntp_last_timestamp_sent[2];
 #endif /* SNTP_CHECK_RESPONSE >= 2 */
 
+/**
+ * Weak callbacks to implement setting system time
+ */
+extern void __attribute__((weak)) sntp_setsystemtime_us(u32_t t, u32_t us)
+{
+  SNTP_SET_SYSTEM_TIME_US(t, us);
+}
+
+extern void __attribute__((weak)) sntp_setsystemtime(u32_t t)
+{
+  SNTP_SET_SYSTEM_TIME(t);
+}
+
 /**
  * SNTP processing of received timestamp
  */
@@ -214,14 +227,14 @@ sntp_process(u32_t *receive_timestamp)
 
 #if SNTP_CALC_TIME_US
   u32_t us = ntohl(receive_timestamp[1]) / 4295;
-  SNTP_SET_SYSTEM_TIME_US(t, us);
+  sntp_setsystemtime_us(t, us);
   /* display local time from GMT time */
   LWIP_DEBUGF(SNTP_DEBUG_TRACE, ("sntp_process: %s, %"U32_F" us", ctime(&tim), us));
 
 #else /* SNTP_CALC_TIME_US */
 
   /* change system time and/or the update the RTC clock */
-  SNTP_SET_SYSTEM_TIME(t);
+  sntp_setsystemtime(t);
   /* display local time from GMT time */
 
   LWIP_DEBUGF(SNTP_DEBUG_TRACE, ("sntp_process: %s", ctime(&tim)));