feat(wifi): Add support for NAPT to WIFI AP (#9478)

Allows another interface's connection to be shared to the AP

Author: me-no-dev

Diff for: libraries/Network/src/NetworkInterface.cpp

@@ -357,6 +357,16 @@ bool NetworkInterface::config(IPAddress local_ip, IPAddress gateway, IPAddress s
 
     esp_netif_flags_t flags = esp_netif_get_flags(_esp_netif);
     if(flags & ESP_NETIF_DHCP_SERVER){
+
+        // Set DNS Server
+        if(d2.ip.u_addr.ip4.addr != 0){
+            err = esp_netif_set_dns_info(_esp_netif, ESP_NETIF_DNS_MAIN, &d2);
+            if(err){
+                log_e("Netif Set DNS Info Failed! 0x%04x: %s", err, esp_err_to_name(err));
+                return false;
+            }
+        }
+
         // Stop DHCPS
         err = esp_netif_dhcps_stop(_esp_netif);
         if(err && err != ESP_ERR_ESP_NETIF_DHCP_ALREADY_STOPPED){
@@ -371,11 +381,6 @@ bool NetworkInterface::config(IPAddress local_ip, IPAddress gateway, IPAddress s
             return false;
         }
 
-        // Set DNS Server
-        if(d2.ip.u_addr.ip4.addr != 0){
-            esp_netif_set_dns_info(_esp_netif, ESP_NETIF_DNS_MAIN, &d2);
-        }
-
         dhcps_lease_t lease;
         lease.enable = true;
         uint8_t CIDR = calculateSubnetCIDR(subnet);
@@ -438,6 +443,17 @@ bool NetworkInterface::config(IPAddress local_ip, IPAddress gateway, IPAddress s
             log_e("DHCPS Set Lease Failed! 0x%04x: %s", err, esp_err_to_name(err));
             return false;
         }
+ 
+        // Offer DNS to DHCP clients
+        if(d2.ip.u_addr.ip4.addr != 0){
+            dhcps_offer_t dhcps_dns_value = OFFER_DNS;
+            err = esp_netif_dhcps_option(_esp_netif, ESP_NETIF_OP_SET, ESP_NETIF_DOMAIN_NAME_SERVER, &dhcps_dns_value, sizeof(dhcps_dns_value));
+            if(err){
+                log_e("Netif Set DHCP Option Failed! 0x%04x: %s", err, esp_err_to_name(err));
+                return false;
+            }
+        }
+        
         // Start DHCPS
         err = esp_netif_dhcps_start(_esp_netif);
         if(err){

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

@@ -20,6 +20,7 @@
 #include <esp_event.h>
 #include <lwip/ip_addr.h>
 #include "dhcpserver/dhcpserver_options.h"
+#include "esp_netif.h"
 
 
 esp_netif_t* get_esp_interface_netif(esp_interface_t interface);
@@ -279,6 +280,24 @@ bool APClass::bandwidth(wifi_bandwidth_t bandwidth){
     return true;
 }
 
+bool APClass::enableNAPT(bool enable){
+    if(!started()) {
+        log_e("AP must be first started to enable/disable NAPT");
+        return false;
+    }
+    esp_err_t err = ESP_OK;
+    if(enable){
+        err = esp_netif_napt_enable(_esp_netif);
+    } else {
+        err = esp_netif_napt_disable(_esp_netif);
+    }
+    if(err){
+        log_e("Could not set enable/disable NAPT! 0x%x: %s", err, esp_err_to_name(err));
+        return false;
+    }
+    return true;
+}
+
 String APClass::SSID(void) const{
     if(!started()){
         return String();

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

@@ -67,9 +67,9 @@ String WiFiAPClass::softAPSSID() const
  * @param gateway       gateway IP
  * @param subnet        subnet mask
  */
-bool WiFiAPClass::softAPConfig(IPAddress local_ip, IPAddress gateway, IPAddress subnet, IPAddress dhcp_lease_start)
+bool WiFiAPClass::softAPConfig(IPAddress local_ip, IPAddress gateway, IPAddress subnet, IPAddress dhcp_lease_start, IPAddress dns)
 {
-    return AP.config(local_ip, gateway, subnet, dhcp_lease_start);
+    return AP.begin() && AP.config(local_ip, gateway, subnet, dhcp_lease_start, dns);
 }
 
 /**

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

@@ -48,6 +48,7 @@ class APClass: public NetworkInterface {
         bool clear();
 
         bool bandwidth(wifi_bandwidth_t bandwidth);
+        bool enableNAPT(bool enable=true);
 
         String SSID(void) const;
         uint8_t stationCount();
@@ -77,7 +78,7 @@ class WiFiAPClass
        return softAP(ssid.c_str(), passphrase.c_str(), channel, ssid_hidden, max_connection, ftm_responder, auth_mode, cipher);
     }
 
-    bool softAPConfig(IPAddress local_ip, IPAddress gateway, IPAddress subnet, IPAddress dhcp_lease_start = (uint32_t) 0);
+    bool softAPConfig(IPAddress local_ip, IPAddress gateway, IPAddress subnet, IPAddress dhcp_lease_start = (uint32_t) 0, IPAddress dns = (uint32_t) 0);
     bool softAPdisconnect(bool wifioff = false);
 
     bool softAPbandwidth(wifi_bandwidth_t bandwidth);