Initialize SoftAP DhcpServer object on demand

Remove dependency on global ctor, and just construct the object when someone asks us to do it. Only dependency right now is netif_git, which is expected to be initialized by the lwip code some time before dhcps_start happens. Removing ip_info from begin(), since we never reference later on. Also removing the specific check for netif id and simplify the ctors. Update tests and recover old nonos-sdk dhcps functions that were not implemented.
esp8266 · d-a-v · Jun 1, 2022 · Apr 19, 2022 · Apr 19, 2022 · Apr 19, 2022
commit 2a46b8fac65d38b5b4effdf25816e892ffe729df
diff --git a/cores/esp8266/LwipDhcpServer-NonOS.cpp b/cores/esp8266/LwipDhcpServer-NonOS.cpp
@@ -1,5 +1,5 @@
 /*
-    lwIPDhcpServer-NonOS.cpp - DHCP server wrapper
+    lwIPDhcpServer-NonOS - DHCP server wrapper
 
     Copyright (c) 2020 esp8266 arduino. All rights reserved.
     This file is part of the esp8266 core for Arduino environment.
@@ -23,41 +23,76 @@
 // these functions must exists as-is with "C" interface,
 // nonos-sdk calls them at boot time and later
 
-#include <lwip/init.h>  // LWIP_VERSION
+#include "LwipDhcpServer-NonOS.h"
 
 #include <lwip/netif.h>
-#include "LwipDhcpServer.h"
 
-extern netif netif_git[2];
-
-// global DHCP instance for softAP interface
-DhcpServer dhcpSoftAP(&netif_git[SOFTAP_IF]);
+// Global static DHCP instance for softAP interface
+// (since the netif object never goes away, even when AP is disabled)
+// Initial version fully emulates nonos-sdk api in DhcpServer class,
+// before trying to further change it and possibly break legacy behaviour
+DhcpServer& dhcpSoftAP() {
+    extern netif netif_git[2];
+    static DhcpServer server(&netif_git[SOFTAP_IF]);
+    return server;
+}
 
 extern "C"
 {
-    void dhcps_start(struct ip_info* info, netif* apnetif)
-    {
-        // apnetif is esp interface, replaced by lwip2's
-        // netif_git[SOFTAP_IF] interface in constructor
-        (void)apnetif;
-
-#if 0
-        // can't use C++ now, global ctors are not initialized yet
-        dhcpSoftAP.begin(info);
-#else
-        (void)info;
-        // initial version: emulate nonos-sdk in DhcpServer class before
-        //                  trying to change legacy behavor
-        // `fw_has_started_softap_dhcps` will be read in DhcpServer::DhcpServer
-        // which is called when c++ ctors are initialized, specifically
-        // dhcpSoftAP initialized with AP interface number above.
-        fw_has_started_softap_dhcps = 1;
-#endif
+    // `ip_info` is useless, since we get the information from the netif directly
+    // `netif` would be netif_git[SOFTAP_IF], which we get from the lwip2 glue
+    void dhcps_start(ip_info *, netif *)
+    {
+        auto& server = dhcpSoftAP();
+        if (!server.isRunning()) {
+            server.begin();
+        }
     }
 
     void dhcps_stop()
     {
-        dhcpSoftAP.end();
+        auto& server = dhcpSoftAP();
+        if (server.isRunning()) {
+            server.end();
+        }
+    }
+
+        // providing the rest of the nonos-sdk API, which was originally removed in 3.0.0
+
+    bool wifi_softap_set_dhcps_lease(dhcps_lease *please)
+    {
+        auto& server = dhcpSoftAP();
+        return server.set_dhcps_lease(please);
+    }
+
+    bool wifi_softap_get_dhcps_lease(dhcps_lease *please)
+    {
+        auto& server = dhcpSoftAP();
+        return server.get_dhcps_lease(please);
+    }
+
+    uint32 wifi_softap_get_dhcps_lease_time()
+    {
+        auto& server = dhcpSoftAP();
+        return server.get_dhcps_lease_time();
+    }
+
+    bool wifi_softap_set_dhcps_lease_time(uint32 minutes)
+    {
+        auto& server = dhcpSoftAP();
+        return server.set_dhcps_lease_time(minutes);
+    }
+
+    bool wifi_softap_reset_dhcps_lease_time()
+    {
+        auto& server = dhcpSoftAP();
+        return server.reset_dhcps_lease_time();
+    }
+
+    bool wifi_softap_add_dhcps_lease(uint8 *macaddr)
+    {
+        auto& server = dhcpSoftAP();
+        return server.add_dhcps_lease(macaddr);
     }
 
 }  // extern "C"
diff --git a/cores/esp8266/LwipDhcpServer.cpp b/cores/esp8266/LwipDhcpServer.cpp
@@ -36,8 +36,6 @@
 
 #include <lwip/init.h>  // LWIP_VERSION
 
-#define DHCPS_LEASE_TIME_DEF (120)
-
 #define USE_DNS
 
 #include "lwip/inet.h"
@@ -166,7 +164,7 @@ const char mem_debug_file[] ICACHE_RODATA_ATTR = __FILE__;
         int ret = 1, errval = (err);                                                               \
         if (errval != ERR_OK)                                                                      \
         {                                                                                          \
-            os_printf("DHCPS ERROR: %s (lwip:%d)\n", what, errval);                                \
+            os_printf("DHCPS ERROR: %s (lwip:%s(%d))\n", what, lwip_strerr(errval), errval);       \
             ret = 0;                                                                               \
         }                                                                                          \
         ret;                                                                                       \
@@ -177,34 +175,11 @@ const char mem_debug_file[] ICACHE_RODATA_ATTR = __FILE__;
 
 const uint32 DhcpServer::magic_cookie = 0x63538263;  // https://tools.ietf.org/html/rfc1497
 
-int fw_has_started_softap_dhcps = 0;
-
 ////////////////////////////////////////////////////////////////////////////////////
 
 DhcpServer::DhcpServer(netif* netif) : _netif(netif)
 {
-    pcb_dhcps        = nullptr;
-    dns_address.addr = 0;
-    plist            = nullptr;
-    offer            = 0xFF;
-    renew            = false;
-    dhcps_lease_time = DHCPS_LEASE_TIME_DEF;  // minute
-
-    if (netif->num == SOFTAP_IF && fw_has_started_softap_dhcps == 1)
-    {
-        // When nonos-sdk starts DHCPS at boot:
-        // 1. `fw_has_started_softap_dhcps` is already initialized to 1
-        // 2. global ctor DhcpServer's `dhcpSoftAP(&netif_git[SOFTAP_IF])` is called
-        // 3. (that's here) => begin(legacy-values) is called
-        ip_info ip = {
-            { 0x0104a8c0 },  // IP 192.168.4.1
-            { 0x00ffffff },  // netmask 255.255.255.0
-            { 0 }            // gateway 0.0.0.0
-        };
-        begin(&ip);
-        fw_has_started_softap_dhcps = 2;  // not 1, ending initial boot sequence
-    }
-};
+}
 
 // wifi_softap_set_station_info is missing in user_interface.h:
 extern "C" void wifi_softap_set_station_info(uint8_t* mac, struct ipv4_addr*);
@@ -1008,17 +983,19 @@ void DhcpServer::init_dhcps_lease(uint32 ip)
 }
 ///////////////////////////////////////////////////////////////////////////////////
 
-bool DhcpServer::begin(struct ip_info* info)
+bool DhcpServer::begin()
 {
     if (pcb_dhcps != nullptr)
     {
         udp_remove(pcb_dhcps);
     }
 
     pcb_dhcps = udp_new();
-    if (pcb_dhcps == nullptr || info == nullptr)
+    if (pcb_dhcps == nullptr)
     {
+#if DHCPS_DEBUG
         os_printf("dhcps_start(): could not obtain pcb\n");
+#endif
         return false;
     }
 
@@ -1030,7 +1007,7 @@ bool DhcpServer::begin(struct ip_info* info)
     ip_2_ip4(&broadcast_dhcps)->addr |= ~ip_2_ip4(&_netif->netmask)->addr;
     // XXXFIXMEIPV6 broadcast address?
 
-    server_address = info->ip;
+    server_address = *ip_2_ip4(&_netif->ip_addr);
     init_dhcps_lease(server_address.addr);
 
     udp_bind(pcb_dhcps, IP_ADDR_ANY, DHCPS_SERVER_PORT);
6D40
@@ -1040,12 +1017,6 @@ bool DhcpServer::begin(struct ip_info* info)
               "pcb_dhcps\n");
 #endif
 
-    if (_netif->num == SOFTAP_IF)
-    {
-        wifi_set_ip_info(SOFTAP_IF, info);  // added for lwip-git, not sure whether useful
-    }
-    _netif->flags |= NETIF_FLAG_UP | NETIF_FLAG_LINK_UP;  // added for lwip-git
-
     return true;
 }
 
@@ -1091,9 +1062,9 @@ void DhcpServer::end()
     }
 }
 
-bool DhcpServer::isRunning()
+bool DhcpServer::isRunning() const
 {
-    return !!_netif->state;
+    return pcb_dhcps != nullptr;
 }
 
 /******************************************************************************
@@ -1342,7 +1313,7 @@ bool DhcpServer::reset_dhcps_lease_time(void)
     {
         return false;
     }
-    dhcps_lease_time = DHCPS_LEASE_TIME_DEF;
+    dhcps_lease_time = DefaultLeaseTime;
     return true;
 }
 

diff --git a/cores/esp8266/LwipDhcpServer.h b/cores/esp8266/LwipDhcpServer.h
@@ -36,14 +36,23 @@
 class DhcpServer
 {
 public:
-    DhcpServer(netif* netif);
+    static constexpr int DefaultLeaseTime = 120 /* seconds */;
+    static constexpr ip_info DefaultIpConfig = {
+        .ip      { 0x0104a8c0 },  // 192.168.4.1
+        .netmask { 0x00ffffff },  // 255.255.255.0
+        .gw      { 0 }            // 0.0.0.0
+    };
+
+    static const uint32 magic_cookie;
+
+    DhcpServer(netif*);
     ~DhcpServer();
 
     void setDns(int num, const ipv4_addr_t* dns);
 
-    bool begin(ip_info* info);
+    bool begin();
     void end();
-    bool isRunning();
+    bool isRunning() const;
 
     // this is the C interface encapsulated in a class
     // (originally dhcpserver.c in lwIP-v1.4 in NonOS-SDK)
@@ -91,25 +100,19 @@ class DhcpServer
     void   dhcps_client_leave(u8* bssid, struct ipv4_addr* ip, bool force);
     uint32 dhcps_client_update(u8* bssid, struct ipv4_addr* ip);
 
-    netif* _netif;
+    netif* _netif = nullptr;
 
-    struct udp_pcb*  pcb_dhcps;
-    ip_addr_t        broadcast_dhcps;
-    struct ipv4_addr server_address;
-    struct ipv4_addr client_address;
-    struct ipv4_addr dns_address;
-    uint32           dhcps_lease_time;
+    udp_pcb*  pcb_dhcps = nullptr;
+    ip_addr_t broadcast_dhcps{};
+    ipv4_addr server_address{};
+    ipv4_addr client_address{};
+    ipv4_addr dns_address{};
+    uint32           dhcps_lease_time = DefaultLeaseTime;
 
     struct dhcps_lease dhcps_lease;
     list_node*         plist;
     uint8              offer;
     bool               renew;
-
-    static const uint32 magic_cookie;
 };
 
-// SoftAP DHCP server always exists and is started on boot
-extern DhcpServer dhcpSoftAP;
-extern "C" int    fw_has_started_softap_dhcps;
-
 #endif  // __DHCPS_H__
diff --git a/libraries/ESP8266WiFi/examples/RangeExtender-NAPT/RangeExtender-NAPT.ino b/libraries/ESP8266WiFi/examples/RangeExtender-NAPT/RangeExtender-NAPT.ino
@@ -54,8 +54,9 @@ void setup() {
   Serial.printf("\nSTA: %s (dns: %s / %s)\n", WiFi.localIP().toString().c_str(), WiFi.dnsIP(0).toString().c_str(), WiFi.dnsIP(1).toString().c_str());
 
   // give DNS servers to AP side
-  dhcpSoftAP.dhcps_set_dns(0, WiFi.dnsIP(0));
-  dhcpSoftAP.dhcps_set_dns(1, WiFi.dnsIP(1));
+  auto& server = dhcpSoftAP();
+  server.dhcps_set_dns(0, WiFi.dnsIP(0));
+  server.dhcps_set_dns(1, WiFi.dnsIP(1));
 
   WiFi.softAPConfig(  // enable AP, with android-compatible google domain
     IPAddress(172, 217, 28, 254), IPAddress(172, 217, 28, 254), IPAddress(255, 255, 255, 0));

diff --git a/libraries/ESP8266WiFi/src/ESP8266WiFiAP.cpp b/libraries/ESP8266WiFi/src/ESP8266WiFiAP.cpp
@@ -37,7 +37,9 @@ extern "C" {
 }
 
 #include "debug.h"
-#include "LwipDhcpServer.h"
+
+#include <LwipDhcpServer.h>
+#include <LwipDhcpServer-NonOS.h>
 
 // -----------------------------------------------------------------------------------------------------------------------
 // ---------------------------------------------------- Private functions ------------------------------------------------
@@ -166,7 +168,8 @@ bool ESP8266WiFiAPClass::softAP(const char* ssid, const char* psk, int channel,
         DEBUG_WIFI("[AP] softap config unchanged\n");
     }
 
-    dhcpSoftAP.end();
+    auto& server = dhcpSoftAP();
+    server.end();
 
     // check IP config
     struct ip_info ip;
@@ -186,7 +189,7 @@ bool ESP8266WiFiAPClass::softAP(const char* ssid, const char* psk, int channel,
         ret = false;
     }
 
-    dhcpSoftAP.begin(&ip);
+    server.begin();
 
     return ret;
 }
@@ -244,21 +247,22 @@ bool ESP8266WiFiAPClass::softAPConfig(IPAddress local_ip, IPAddress gateway, IPA
     dhcp_lease.end_ip.addr = ip.v4();
     DEBUG_WIFI("[APConfig] DHCP IP end: %s\n", ip.toString().c_str());
 
-    if(!dhcpSoftAP.set_dhcps_lease(&dhcp_lease))
+    auto& server = dhcpSoftAP();
+    if(!server.set_dhcps_lease(&dhcp_lease))
     {
         DEBUG_WIFI("[APConfig] wifi_set_ip_info failed!\n");
         ret = false;
     }
 
     // set lease time to 720min --> 12h
-    if(!dhcpSoftAP.set_dhcps_lease_time(720))
+    if(!server.set_dhcps_lease_time(720))
     {
         DEBUG_WIFI("[APConfig] wifi_softap_set_dhcps_lease_time failed!\n");
         ret = false;
     }
 
     uint8 mode = info.gw.addr ? 1 : 0;
-    if(!dhcpSoftAP.set_dhcps_offer_option(OFFER_ROUTER, &mode))
+    if(!server.set_dhcps_offer_option(OFFER_ROUTER, &mode))
     {
         DEBUG_WIFI("[APConfig] wifi_softap_set_dhcps_offer_option failed!\n");
         ret = false;

diff --git a/tests/host/common/user_interface.cpp b/tests/host/common/user_interface.cpp
@@ -64,23 +64,25 @@ bool DhcpServer::set_dhcps_offer_option(uint8 level, void* optarg)
 
 void DhcpServer::end() { }
 
-bool DhcpServer::begin(struct ip_info* info)
+bool DhcpServer::begin()
 {
-    (void)info;
     return false;
 }
 
-DhcpServer::DhcpServer(netif* netif)
+DhcpServer::DhcpServer(netif*)
 {
-    (void)netif;
 }
 
 DhcpServer::~DhcpServer()
 {
     end();
 }
 
-DhcpServer dhcpSoftAP(nullptr);
+DhcpServer& dhcpSoftAP()
+{
+    static DhcpServer server(nullptr);
+    return server;
+}
 
 extern "C"
 {