From 097282a8e3f85958747430d9931ce0a545d37700 Mon Sep 17 00:00:00 2001
From: David Cermak <cermak@espressif.com>
Date: Mon, 22 Oct 2018 16:45:42 +0200
Subject: [PATCH] mdns: fixed crashes on network changes

1) two events AP_STOP, AP_START shortly after each other may cause IGMP config on already stopped netif
2) not properly locked sending packets to queue from timer task

closes #2580
---
 components/mdns/mdns.c                           |  3 ++-
 components/mdns/mdns_networking.c                |  6 ++++++
 components/tcpip_adapter/include/tcpip_adapter.h | 10 ++++++++++
 components/tcpip_adapter/tcpip_adapter_lwip.c    |  9 +++++++++
 4 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/components/mdns/mdns.c b/components/mdns/mdns.c
index 38d678268..443b39846 100644
--- a/components/mdns/mdns.c
+++ b/components/mdns/mdns.c
@@ -3794,13 +3794,14 @@ static esp_err_t _mdns_send_search_action(mdns_action_type_t type, mdns_search_o
  */
 static void _mdns_scheduler_run()
 {
+    MDNS_SERVICE_LOCK();
     mdns_tx_packet_t * p = _mdns_server->tx_queue_head;
     mdns_action_t * action = NULL;
 
     if (!p) {
+        MDNS_SERVICE_UNLOCK();
         return;
     }
-    MDNS_SERVICE_LOCK();
     if ((int32_t)(p->send_at - (xTaskGetTickCount() * portTICK_PERIOD_MS)) < 0) {
         action = (mdns_action_t *)malloc(sizeof(mdns_action_t));
         if (action) {
diff --git a/components/mdns/mdns_networking.c b/components/mdns/mdns_networking.c
index 4e64e36cf..9aac3ec89 100644
--- a/components/mdns/mdns_networking.c
+++ b/components/mdns/mdns_networking.c
@@ -62,6 +62,12 @@ static esp_err_t _udp_join_group(tcpip_adapter_if_t tcpip_if, mdns_ip_protocol_t
 {
     struct netif * netif = NULL;
     void * nif = NULL;
+
+    if (!tcpip_adapter_is_netif_up(tcpip_if)) {
+        // Network interface went down before event propagated, skipping IGMP config
+        return ESP_ERR_INVALID_STATE;
+    }
+
     esp_err_t err = tcpip_adapter_get_netif(tcpip_if, &nif);
     if (err) {
         return ESP_ERR_INVALID_ARG;
diff --git a/components/tcpip_adapter/include/tcpip_adapter.h b/components/tcpip_adapter/include/tcpip_adapter.h
index 205c05fab..7d9e4ad8c 100644
--- a/components/tcpip_adapter/include/tcpip_adapter.h
+++ b/components/tcpip_adapter/include/tcpip_adapter.h
@@ -618,6 +618,16 @@ esp_err_t tcpip_adapter_get_hostname(tcpip_adapter_if_t tcpip_if, const char **h
  */
 esp_err_t tcpip_adapter_get_netif(tcpip_adapter_if_t tcpip_if, void ** netif);
 
+/**
+ * @brief  Test if supplied interface is up or down
+ *
+ * @param[in]   tcpip_if: the interface which we will get the hostname
+ *
+ * @return  true:  tcpip_if is UP
+ *          false: tcpip_if id DOWN
+ */
+bool tcpip_adapter_is_netif_up(tcpip_adapter_if_t tcpip_if);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/components/tcpip_adapter/tcpip_adapter_lwip.c b/components/tcpip_adapter/tcpip_adapter_lwip.c
index 85a76da81..f1c32b0e5 100644
--- a/components/tcpip_adapter/tcpip_adapter_lwip.c
+++ b/components/tcpip_adapter/tcpip_adapter_lwip.c
@@ -1222,4 +1222,13 @@ esp_err_t tcpip_adapter_get_netif(tcpip_adapter_if_t tcpip_if, void ** netif)
     return ESP_OK;
 }
 
+bool tcpip_adapter_is_netif_up(tcpip_adapter_if_t tcpip_if)
+{
+    if (esp_netif[tcpip_if] != NULL && netif_is_up(esp_netif[tcpip_if])) {
+        return true;
+    } else {
+        return false;
+    }
+}
+
 #endif /* CONFIG_TCPIP_LWIP */