esp-netif: use dhcp server netmask

Use the configured esp-netif netmask to update the dhcp struct when
starting the server or starting the netif itself.
Use the netmask in dhcps setters and getters.

components/esp_netif/include/esp_netif_types.h

@@ -73,6 +73,7 @@ typedef enum{
 
 /** @brief Supported options for DHCP client or DHCP server */
 typedef enum{
+    ESP_NETIF_SUBNET_MASK                   = 1,    /**< Network mask */
     ESP_NETIF_DOMAIN_NAME_SERVER            = 6,    /**< Domain name server */
     ESP_NETIF_ROUTER_SOLICITATION_ADDRESS   = 32,   /**< Solicitation router address */
     ESP_NETIF_REQUESTED_IP_ADDRESS          = 50,   /**< Request specific IP address */
@@ -212,4 +213,4 @@ typedef esp_err_t (*esp_netif_receive_t)(esp_netif_t *esp_netif, void *buffer, s
 }
 #endif
 
-#endif // _ESP_NETIF_TYPES_H_
+#endif // _ESP_NETIF_TYPES_H_

components/esp_netif/lwip/esp_netif_lwip.c

@@ -627,8 +627,11 @@ static esp_err_t esp_netif_start_api(esp_netif_api_msg_t *msg)
             if (p_netif != NULL && netif_is_up(p_netif)) {
                 esp_netif_ip_info_t *default_ip = esp_netif->ip_info;
                 ip4_addr_t lwip_ip;
+                ip4_addr_t lwip_netmask;
                 memcpy(&lwip_ip, &default_ip->ip, sizeof(struct ip4_addr));
+                memcpy(&lwip_netmask, &default_ip->netmask, sizeof(struct ip4_addr));
                 dhcps_set_new_lease_cb(esp_netif_dhcps_cb);
+                dhcps_set_option_info(SUBNET_MASK, (void*)&lwip_netmask, sizeof(lwip_netmask));
                 dhcps_start(p_netif, lwip_ip);
                 esp_netif->dhcps_status = ESP_NETIF_DHCP_STARTED;
                 ESP_LOGD(TAG, "DHCP server started successfully");
@@ -986,8 +989,11 @@ static esp_err_t esp_netif_dhcps_start_api(esp_netif_api_msg_t *msg)
     if (p_netif != NULL && netif_is_up(p_netif)) {
         esp_netif_ip_info_t *default_ip = esp_netif->ip_info;
         ip4_addr_t lwip_ip;
+        ip4_addr_t lwip_netmask;
         memcpy(&lwip_ip, &default_ip->ip, sizeof(struct ip4_addr));
+        memcpy(&lwip_netmask, &default_ip->netmask, sizeof(struct ip4_addr));
         dhcps_set_new_lease_cb(esp_netif_dhcps_cb);
+        dhcps_set_option_info(SUBNET_MASK, (void*)&lwip_netmask, sizeof(lwip_netmask));
         dhcps_start(p_netif, lwip_ip);
         esp_netif->dhcps_status = ESP_NETIF_DHCP_STARTED;
         ESP_LOGD(TAG, "DHCP server started successfully");
@@ -1547,6 +1553,7 @@ esp_err_t esp_netif_dhcps_option(esp_netif_t *esp_netif, esp_netif_dhcp_option_m
                 *(uint32_t *)opt_val = *(uint32_t *)opt_info;
                 break;
             }
+            case ESP_NETIF_SUBNET_MASK:
             case REQUESTED_IP_ADDRESS: {
                 memcpy(opt_val, opt_info, opt_len);
                 break;
@@ -1584,6 +1591,10 @@ esp_err_t esp_netif_dhcps_option(esp_netif_t *esp_netif, esp_netif_dhcp_option_m
                 }
                 break;
             }
+            case ESP_NETIF_SUBNET_MASK: {
+                memcpy(opt_info, opt_val, opt_len);
+                break;
+            }
             case REQUESTED_IP_ADDRESS: {
                 esp_netif_ip_info_t info;
                 uint32_t softap_ip = 0;