Further hiding BearSSL for ESP8266 patching

This makes it at least compile for ESP32 again. Unfortunately
ESP32 chose mbedtls rather than BearSSL, and the APIs are quite
different, so this is the most minimal porting only so far.

Author: dirkmueller

airrohr-firmware/airrohr-firmware.ino

@@ -337,7 +337,6 @@ enum class PmSensorCmd {
 };
 
 LoggerConfig loggerConfigs[LoggerCount];
-BearSSL::X509List x509_dst_root_ca(dst_root_ca_x3);
 
 long int sample_count = 0;
 bool htu21d_init_failed = false;
@@ -1092,30 +1091,35 @@ static void writeConfig() {
  * Prepare information for data Loggers                          *
  *****************************************************************/
 static void createLoggerConfigs() {
+#if defined(ESP8266)
+	auto new_session = []() { return new BearSSL::Session; };
+#else
+	auto new_session = []() { return nullptr; };
+#endif
 	if (cfg::send2dusti) {
 		loggerConfigs[LoggerSensorCommunity].destport = 80;
 		if (cfg::ssl_dusti) {
 			loggerConfigs[LoggerSensorCommunity].destport = 443;
-			loggerConfigs[LoggerSensorCommunity].session = new BearSSL::Session;
+			loggerConfigs[LoggerSensorCommunity].session = new_session();
 		}
 	}
 	loggerConfigs[LoggerMadavi].destport = PORT_MADAVI;
 	if (cfg::send2madavi && cfg::ssl_madavi) {
 		loggerConfigs[LoggerMadavi].destport = 443;
-		loggerConfigs[LoggerMadavi].session = new BearSSL::Session;
+		loggerConfigs[LoggerMadavi].session = new_session();
 	}
 	loggerConfigs[LoggerSensemap].destport = PORT_SENSEMAP;
-	loggerConfigs[LoggerSensemap].session = new BearSSL::Session;
+	loggerConfigs[LoggerSensemap].session = new_session();
 	loggerConfigs[LoggerFSapp].destport = PORT_FSAPP;
-	loggerConfigs[LoggerFSapp].session = new BearSSL::Session;
+	loggerConfigs[LoggerFSapp].session = new_session();
 	loggerConfigs[Loggeraircms].destport = PORT_AIRCMS;
 	loggerConfigs[LoggerInflux].destport = cfg::port_influx;
 	if (cfg::send2influx && cfg::ssl_influx) {
-		loggerConfigs[LoggerInflux].session = new BearSSL::Session;
+		loggerConfigs[LoggerInflux].session = new_session();
 	}
 	loggerConfigs[LoggerCustom].destport = cfg::port_custom;
 	if (cfg::send2custom && (cfg::ssl_custom || (cfg::port_custom == 443))) {
-		loggerConfigs[LoggerCustom].session = new BearSSL::Session;
+		loggerConfigs[LoggerCustom].session = new_session();
 	}
 }
 
@@ -2339,6 +2343,9 @@ static void connectWifi() {
 	last_signal_strength = WiFi.RSSI();
 }
 
+#if defined(ESP8266)
+BearSSL::X509List x509_dst_root_ca(dst_root_ca_x3);
+
 static void configureCACertTrustAnchor(WiFiClientSecure* client) {
 	constexpr time_t fw_built_year = (__DATE__[ 7] - '0') * 1000 + \
 							  (__DATE__[ 8] - '0') *  100 + \
@@ -2352,12 +2359,14 @@ static void configureCACertTrustAnchor(WiFiClientSecure* client) {
 		client->setTrustAnchors(&x509_dst_root_ca);
 	}
 }
+#endif
 
 static WiFiClient* getNewLoggerWiFiClient(const LoggerEntry logger) {
 
 	WiFiClient* _client;
 	if (loggerConfigs[logger].session) {
 		_client = new WiFiClientSecure;
+#if defined(ESP8266)
 		static_cast<WiFiClientSecure*>(_client)->setSession(loggerConfigs[logger].session);
 		static_cast<WiFiClientSecure*>(_client)->setBufferSizes(1024, TCP_MSS > 1024 ? 2048 : 1024);
 		switch (logger) {
@@ -2370,6 +2379,7 @@ static WiFiClient* getNewLoggerWiFiClient(const LoggerEntry logger) {
 		default:
 			configureCACertTrustAnchor(static_cast<WiFiClientSecure*>(_client));
 		}
+#endif
 	} else {
 		_client = new WiFiClient;
 	}

airrohr-firmware/ext_def.h

@@ -45,7 +45,11 @@ enum LoggerEntry {
 struct LoggerConfig {
     uint16_t destport;
     uint16_t _unused;
+#if defined(ESP8266)
     BearSSL::Session* session;
+#else
+    void* session;
+#endif
 };
 
 // IMPORTANT: NO MORE CHANGES TO VARIABLE NAMES NEEDED FOR EXTERNAL APIS