Support getting NTP server from DHCP lease

include/lwip/lwipopts.h

@@ -53,6 +53,7 @@ extern "C" {
 #define LWIP_POSIX_SOCKETS_IO_NAMES 0
 #define LWIP_STATS 0
 #define LWIP_TCP_KEEPALIVE 1
+#define LWIP_DHCP_GET_NTP_SRV 1
 
 #define SYS_LIGHTWEIGHT_PROT 1
 

lwip/src/core/ipv4/dhcp.c

@@ -663,8 +663,11 @@ dhcp_handle_ack(struct netif *netif, struct dhcp_msg *msg_in)
   /* NTP servers */
   for (n = 0; (n < LWIP_DHCP_MAX_NTP_SERVERS) && dhcp_option_given(dhcp, DHCP_OPTION_IDX_NTP_SERVER + n); n++) {
     ip4_addr_set_u32(&ntp_server_addrs[n], lwip_htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_NTP_SERVER + n)));
+    if (n == 0) {
+      ip4_addr_set_u32(&dhcp->offered_ntp_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_NTP_SERVER)));
+    }
   }
-  dhcp_set_ntp_servers(n, ntp_server_addrs);
+  //dhcp_set_ntp_servers(n, ntp_server_addrs);
 #endif /* LWIP_DHCP_GET_NTP_SRV */
 
 #if LWIP_DHCP_PROVIDE_DNS_SERVERS

lwip/src/include/lwip/dhcp.h

@@ -91,6 +91,7 @@ struct dhcp
   ip4_addr_t offered_sn_mask;
   ip4_addr_t offered_gw_addr;
   ip4_addr_t offered_dns_addr;
+  ip4_addr_t offered_ntp_addr;
 
   u32_t offered_t0_lease; /* lease period (in seconds) */
   u32_t offered_t1_renew; /* recommended renew time (usually 50% of lease period) */

src/esp8266/sdk_lwip/src/core/dhcp.c

@@ -113,16 +113,22 @@ static const char mem_debug_file[] ICACHE_RODATA_ATTR = __FILE__;
  * This might be moved into the struct dhcp (not necessarily since
  * lwIP is single-threaded and the array is only used while in recv
  * callback). */
-#define DHCP_OPTION_IDX_OVERLOAD    0
-#define DHCP_OPTION_IDX_MSG_TYPE    1
-#define DHCP_OPTION_IDX_SERVER_ID   2
-#define DHCP_OPTION_IDX_LEASE_TIME  3
-#define DHCP_OPTION_IDX_T1          4
-#define DHCP_OPTION_IDX_T2          5
-#define DHCP_OPTION_IDX_SUBNET_MASK 6
-#define DHCP_OPTION_IDX_ROUTER      7
-#define DHCP_OPTION_IDX_DNS_SERVER	8
-#define DHCP_OPTION_IDX_MAX         (DHCP_OPTION_IDX_DNS_SERVER + DNS_MAX_SERVERS)
+#define NTP_MAX_SERVERS 1
+enum dhcp_option_idx {
+  DHCP_OPTION_IDX_OVERLOAD = 0,
+  DHCP_OPTION_IDX_MSG_TYPE,
+  DHCP_OPTION_IDX_SERVER_ID,
+  DHCP_OPTION_IDX_LEASE_TIME,
+  DHCP_OPTION_IDX_T1,
+  DHCP_OPTION_IDX_T2,
+  DHCP_OPTION_IDX_SUBNET_MASK,
+  DHCP_OPTION_IDX_ROUTER,
+  DHCP_OPTION_IDX_DNS_SERVER,
+  DHCP_OPTION_IDX_DNS_SERVER_LAST = DHCP_OPTION_IDX_DNS_SERVER + DNS_MAX_SERVERS - 1,
+  DHCP_OPTION_IDX_NTP_SERVER,
+  DHCP_OPTION_IDX_NTP_SERVER_LAST = DHCP_OPTION_IDX_NTP_SERVER + NTP_MAX_SERVERS - 1,
+  DHCP_OPTION_IDX_MAX
+};
 
 /** Holds the decoded option values, only valid while in dhcp_recv.
     @todo: move this into struct dhcp? */
@@ -614,23 +620,27 @@ dhcp_handle_ack(struct netif *netif)
   if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_ROUTER)) {
     ip4_addr_set_u32(&dhcp->offered_gw_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_ROUTER)));
   }
-  
+
 #if LWIP_DNS
   /* DNS servers */
   n = 0;
   if(manual_set_flag == false) {
-	  while(dhcp_option_given(dhcp, DHCP_OPTION_IDX_DNS_SERVER + n) && (n < DNS_MAX_SERVERS)) {
-		ip_addr_t dns_addr;
-		ip4_addr_set_u32(&dns_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_DNS_SERVER + n)));
-		dns_setserver(n, &dns_addr);
-		n++;
-	  }
+    while(dhcp_option_given(dhcp, DHCP_OPTION_IDX_DNS_SERVER + n) && (n < DNS_MAX_SERVERS)) {
+      ip_addr_t dns_addr;
+      ip4_addr_set_u32(&dns_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_DNS_SERVER + n)));
+      dns_setserver(n, &dns_addr);
+      n++;
+    }
   }
 #endif /* LWIP_DNS */
   ip_addr_set_zero(&dhcp->offered_dns_addr);
   if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_DNS_SERVER)) {
     ip4_addr_set_u32(&dhcp->offered_dns_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_DNS_SERVER)));
   }
+  ip_addr_set_zero(&dhcp->offered_ntp_addr);
+  if (dhcp_option_given(dhcp, DHCP_OPTION_IDX_NTP_SERVER)) {
+    ip4_addr_set_u32(&dhcp->offered_ntp_addr, htonl(dhcp_get_option_value(dhcp, DHCP_OPTION_IDX_NTP_SERVER)));
+  }
 }
 
 /** Set a statically allocated struct dhcp to work with.
@@ -1567,6 +1577,14 @@ dhcp_parse_reply(struct dhcp *dhcp, struct pbuf *p)
         LWIP_ASSERT("len == 4", len == 4);
         decode_idx = DHCP_OPTION_IDX_LEASE_TIME;
         break;
+      case (DHCP_OPTION_NTP):
+        /* special case: there might be more than one server */
+        LWIP_ERROR("len %% 4 == 0", len % 4 == 0, return ERR_VAL;);
+        /* limit number of NTP servers */
+        decode_len = LWIP_MIN(len, 4 * NTP_MAX_SERVERS);
+        LWIP_ERROR("len >= decode_len", len >= decode_len, return ERR_VAL;);
+        decode_idx = DHCP_OPTION_IDX_NTP_SERVER;
+        break;
       case(DHCP_OPTION_OVERLOAD):
         LWIP_ASSERT("len == 1", len == 1);
         decode_idx = DHCP_OPTION_IDX_OVERLOAD;

src/mgos_lwip.c

@@ -25,8 +25,7 @@
 #include "lwip/netif.h"
 #include "lwip/tcpip.h"
 
-bool mgos_lwip_if_get_ip_info(const struct netif *nif,
-                              const char *dns_override,
+bool mgos_lwip_if_get_ip_info(const struct netif *nif, const char *dns_override,
                               struct mgos_net_ip_info *ip_info) {
   if (nif == NULL || !(nif->flags & NETIF_FLAG_UP)) return false;
   memset(ip_info, 0, sizeof(*ip_info));
@@ -39,21 +38,22 @@ bool mgos_lwip_if_get_ip_info(const struct netif *nif,
     struct dhcp *dhcp = netif_dhcp_data(nif);
     if (dhcp != NULL) {
       ip_info->dns.sin_addr.s_addr = ip4_addr_get_u32(&dhcp->offered_dns_addr);
+      ip_info->ntp.sin_addr.s_addr = ip4_addr_get_u32(&dhcp->offered_ntp_addr);
     }
   }
   return true;
 }
 
 #if CS_PLATFORM != CS_P_ESP32 && CS_PLATFORM != CS_P_ESP8266
 static void tcpip_init_done(void *arg) {
-  *((bool *)arg) = true;
+  *((bool *) arg) = true;
 }
 #endif
 
 bool mgos_lwip_init(void) {
 #if CS_PLATFORM != CS_P_ESP32 && CS_PLATFORM != CS_P_ESP8266
   volatile bool lwip_inited = false;
-  tcpip_init(tcpip_init_done, (void *)&lwip_inited);
+  tcpip_init(tcpip_init_done, (void *) &lwip_inited);
   while (!lwip_inited) {
   }
 #endif