dns: Add on-demand timer config for DNS timer

2.1.3-esp: 6b0bfc2e lwip:optimization lwip dns timer

contrib/examples/example_app/lwipopts.h

@@ -328,6 +328,7 @@ void lwip_example_app_platform_assert(const char *msg, int line, const char *fil
 #define ESP_LWIP_IGMP_TIMERS_ONDEMAND ESP_LWIP
 #define ESP_LWIP_MLD6_TIMERS_ONDEMAND ESP_LWIP
 #define ESP_LWIP_DHCP_FINE_TIMERS_ONDEMAND ESP_LWIP
+#define ESP_LWIP_DNS_TIMERS_ONDEMAND ESP_LWIP
 #define ESP_DNS ESP_LWIP
 #define ESP_LWIP_ARP ESP_LWIP
 

src/core/dns.c

@@ -94,6 +94,12 @@
 #include "lwip/memp.h"
 #include "lwip/dns.h"
 #include "lwip/prot/dns.h"
+#include "lwip/timeouts.h"
+
+#if ESP_LWIP_DNS_TIMERS_ONDEMAND
+#include "stdbool.h"
+static bool s_is_tmr_start = false;
+#endif /* ESP_LWIP_DNS_TIMERS_ONDEMAND */
 
 #include <string.h>
 #if ESP_DNS
@@ -412,6 +418,17 @@ dns_getserver(u8_t numdns)
   }
 }
 
+#if ESP_LWIP_DNS_TIMERS_ONDEMAND
+/**
+ * Wrapper function with matching prototype which calls the actual callback
+ */
+static void dns_timeout_cb(void *arg)
+{
+  LWIP_UNUSED_ARG(arg);
+  dns_tmr();
+}
+#endif /* ESP_LWIP_DNS_TIMERS_ONDEMAND */
+
 /**
  * The DNS resolver client timer - handle retries and timeouts and should
  * be called every DNS_TMR_INTERVAL milliseconds (every second by default).
@@ -419,8 +436,26 @@ dns_getserver(u8_t numdns)
 void
 dns_tmr(void)
 {
+#if ESP_LWIP_DNS_TIMERS_ONDEMAND
+  bool tmr_restart = false;
+  u8_t i = 0;
+#endif /* ESP_LWIP_DNS_TIMERS_ONDEMAND */
   LWIP_DEBUGF(DNS_DEBUG, ("dns_tmr: dns_check_entries\n"));
   dns_check_entries();
+#if ESP_LWIP_DNS_TIMERS_ONDEMAND
+  for (i = 0; i < DNS_TABLE_SIZE; ++i) {
+    if (dns_table[i].state != DNS_STATE_UNUSED) {
+      tmr_restart = true;
+      break;
+    }
+  }
+  if (tmr_restart) {
+    sys_timeout(DNS_TMR_INTERVAL, dns_timeout_cb, NULL);
+  } else {
+    sys_untimeout(dns_timeout_cb, NULL);
+    s_is_tmr_start = false;
+  }
+#endif/* ESP_LWIP_DNS_TIMERS_ONDEMAND */
 }
 
 #if DNS_LOCAL_HOSTLIST
@@ -1555,6 +1590,12 @@ dns_enqueue(const char *name, size_t hostnamelen, dns_found_callback found,
 
   /* force to send query without waiting timer */
   dns_check_entry(i);
+#if ESP_LWIP_DNS_TIMERS_ONDEMAND
+  if (!s_is_tmr_start) {
+    sys_timeout(DNS_TMR_INTERVAL, dns_timeout_cb, NULL);
+    s_is_tmr_start = true;
+  }
+#endif /* ESP_LWIP_DNS_TIMERS_ONDEMAND */
 
   /* dns query is enqueued */
   return ERR_INPROGRESS;

src/core/timeouts.c

@@ -100,7 +100,7 @@ const struct lwip_cyclic_timer lwip_cyclic_timers[] = {
   {IGMP_TMR_INTERVAL, HANDLER(igmp_tmr)},
 #endif /* LWIP_IGMP */
 #endif /* LWIP_IPV4 */
-#if LWIP_DNS
+#if LWIP_DNS && !ESP_LWIP_DNS_TIMERS_ONDEMAND
   {DNS_TMR_INTERVAL, HANDLER(dns_tmr)},
 #endif /* LWIP_DNS */
 #if LWIP_IPV6

src/include/lwip/opt.h

@@ -498,7 +498,7 @@
  * The number of sys timeouts used by the core stack (not apps)
  * The default number of timeouts is calculated here for all enabled modules.
  */
-#define LWIP_NUM_SYS_TIMEOUT_INTERNAL   (LWIP_TCP + IP_REASSEMBLY + LWIP_ARP + (ESP_LWIP_DHCP_FINE_TIMERS_ONDEMAND ? LWIP_DHCP : 2*LWIP_DHCP) + LWIP_ACD + (ESP_LWIP_IGMP_TIMERS_ONDEMAND ? 0 : LWIP_IGMP) + LWIP_DNS + PPP_NUM_TIMEOUTS + (LWIP_IPV6 * (1 + LWIP_IPV6_REASS + (ESP_LWIP_MLD6_TIMERS_ONDEMAND ? 0 : LWIP_IPV6_MLD) + LWIP_IPV6_DHCP6)))
+#define LWIP_NUM_SYS_TIMEOUT_INTERNAL   (LWIP_TCP + IP_REASSEMBLY + LWIP_ARP + (ESP_LWIP_DHCP_FINE_TIMERS_ONDEMAND ? LWIP_DHCP : 2*LWIP_DHCP) + LWIP_ACD + (ESP_LWIP_IGMP_TIMERS_ONDEMAND ? 0 : LWIP_IGMP) + (ESP_LWIP_DNS_TIMERS_ONDEMAND ? 0 : LWIP_DNS) + PPP_NUM_TIMEOUTS + (LWIP_IPV6 * (1 + LWIP_IPV6_REASS + (ESP_LWIP_MLD6_TIMERS_ONDEMAND ? 0 : LWIP_IPV6_MLD) + LWIP_IPV6_DHCP6)))
 
 /**
  * MEMP_NUM_SYS_TIMEOUT: the number of simultaneously active timeouts.

test/unit/lwipopts.h

@@ -164,6 +164,7 @@ u32_t esp_random(void);
 #define ESP_LWIP_MLD6_TIMERS_ONDEMAND           1
 #define DNS_FALLBACK_SERVER_INDEX       (DNS_MAX_SERVERS - 1)
 #define ESP_LWIP_DHCP_FINE_TIMERS_ONDEMAND      1
+#define ESP_LWIP_DNS_TIMERS_ONDEMAND            1
 
 #else
 #define ESP_LWIP                                0
@@ -175,6 +176,10 @@ u32_t esp_random(void);
 #define ESP_LWIP_DHCP_FINE_TIMERS_ONDEMAND      0
 #endif
 
+#ifndef ESP_LWIP_DNS_TIMERS_ONDEMAND
+#define ESP_LWIP_DNS_TIMERS_ONDEMAND            0
+#endif
+
 #endif /* ESP_LWIP */
 
 #endif /* LWIP_HDR_LWIPOPTS_H */