Fixes DHCP Server Lease Range for any AP Server Static IP Address (#6296)

* Fixes DHCP Server Lease Range for any AP Server Static IP Address

* Fixes DHCP in APMode when Static IP is out of subnet range

Author: SuGlider

Diff for: libraries/WiFi/src/WiFiAP.cpp

@@ -205,23 +205,7 @@ bool WiFiAPClass::softAPConfig(IPAddress local_ip, IPAddress gateway, IPAddress
     }
 
     err = set_esp_interface_ip(ESP_IF_WIFI_AP, local_ip, gateway, subnet);
-
-    // testing effectiveness of the operation beyond internal DHCP Client process
-	esp_netif_ip_info_t ip;
-    if(esp_netif_get_ip_info(get_esp_interface_netif(ESP_IF_WIFI_AP), &ip) != ESP_OK){
-    	log_e("Netif Get IP Failed!");
-    	return false;
-    }
-    bool ip_ok = IPAddress(ip.ip.addr) == local_ip;
-    bool gw_ok = IPAddress(ip.gw.addr) == gateway;
-    bool mk_ok = IPAddress(ip.netmask.addr) == subnet;
-
-    if (ip_ok && gw_ok && mk_ok) {
-        return true;
-    } else {
-        log_e("Failed setting: %s %s %s", ip_ok ? "" : "Static IP", gw_ok ? "" : "- Gateway", mk_ok ? "" : "- Netmask"); 
-        return false;
-    }
+    return err == ESP_OK;
 }
 
 

Diff for: libraries/WiFi/src/WiFiGeneric.cpp

@@ -138,9 +138,20 @@ esp_err_t set_esp_interface_ip(esp_interface_t interface, IPAddress local_ip=IPA
 
         dhcps_lease_t lease;
         lease.enable = true;
-        lease.start_ip.addr = static_cast<uint32_t>(local_ip) + (1 << 24);
-        lease.end_ip.addr = static_cast<uint32_t>(local_ip) + (11 << 24);
-
+        uint32_t dhcp_ipaddr = static_cast<uint32_t>(local_ip);
+        // prevents DHCP lease range to overflow subnet/24 range
+        // there will be 11 addresses for DHCP to lease
+        uint8_t leaseStart = (uint8_t)(~subnet[3] - 12);  
+        if ((local_ip[3]) < leaseStart) {
+            lease.start_ip.addr = dhcp_ipaddr + (1 << 24);
+            lease.end_ip.addr = dhcp_ipaddr + (11 << 24);
+        } else {
+            // make range stay in the begining of the netmask range
+            dhcp_ipaddr = (dhcp_ipaddr & 0x00FFFFFF);
+            lease.start_ip.addr = dhcp_ipaddr + (1 << 24);
+            lease.end_ip.addr = dhcp_ipaddr + (11 << 24);
+        }
+        log_v("DHCP Server Range: %s to %s", IPAddress(lease.start_ip.addr).toString(), IPAddress(lease.end_ip.addr).toString());
         err = tcpip_adapter_dhcps_option(
             (tcpip_adapter_dhcp_option_mode_t)TCPIP_ADAPTER_OP_SET,
             (tcpip_adapter_dhcp_option_id_t)REQUESTED_IP_ADDRESS,