split out ip discoverey and improve it from a bunch of punning

src/dpp/discordvoiceclient.cpp

@@ -420,47 +420,6 @@ uint64_t discord_voice_client::get_timescale() {
 	return timescale;
 }
 
-std::string discord_voice_client::discover_ip() {
-	dpp::socket newfd = SOCKET_ERROR;
-	unsigned char packet[74] = { 0 };
-	(*(uint16_t*)(packet)) = htons(0x01);
-	(*(uint16_t*)(packet + 2)) = htons(70);
-	(*(uint32_t*)(packet + 4)) = htonl((uint32_t)this->ssrc);
-	if ((newfd = ::socket(AF_INET, SOCK_DGRAM, 0)) >= 0) {
-		sockaddr_in servaddr{};
-		memset(&servaddr, 0, sizeof(sockaddr_in));
-		servaddr.sin_family = AF_INET;
-		servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
-		servaddr.sin_port = htons(0);
-		if (bind(newfd, (sockaddr*)&servaddr, sizeof(servaddr)) < 0) {
-			log(ll_warning, "Could not bind socket for IP discovery");
-			return "";
-		}
-		memset(&servaddr, 0, sizeof(servaddr));
-		servaddr.sin_family = AF_INET;
-		servaddr.sin_port = htons(this->port);
-		servaddr.sin_addr.s_addr = inet_addr(this->ip.c_str());
-		if (::connect(newfd, (const sockaddr*)&servaddr, sizeof(sockaddr_in)) < 0) {
-			log(ll_warning, "Could not connect socket for IP discovery");
-			return "";
-		}
-		if (::send(newfd, (const char*)packet, 74, 0) == -1) {
-			log(ll_warning, "Could not send packet for IP discovery");
-			return "";
-		}
-		if (recv(newfd, (char*)packet, 74, 0) == -1) {
-			log(ll_warning, "Could not receive packet for IP discovery");
-			return "";
-		}
-
-		close_socket(newfd);
-
-		//utility::debug_dump(packet, 74);
-		return std::string((const char*)(packet + 8));
-	}
-	return "";
-}
-
 discord_voice_client& discord_voice_client::set_iteration_interval(uint16_t interval) {
 	this->iteration_interval = interval;
 	return *this;

src/dpp/voice/enabled/discover_ip.cpp

@@ -0,0 +1,94 @@
+/************************************************************************************
+ *
+ * D++, A Lightweight C++ library for Discord
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ * Copyright 2021 Craig Edwards and D++ contributors
+ * (https://github.com/brainboxdotcc/DPP/graphs/contributors)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ ************************************************************************************/
+
+#include <dpp/exception.h>
+#include <dpp/discordvoiceclient.h>
+#include "enabled.h"
+
+namespace dpp {
+
+/**
+ * https://discord.com/developers/docs/topics/voice-connections#ip-discovery
+ */
+
+#pragma pack(push, 1)
+struct ip_discovery_packet {
+	uint16_t type;
+	uint16_t length;
+	uint32_t ssrc;
+	char address[64]{0}; // NOLINT
+	uint16_t port;
+
+	ip_discovery_packet() = delete;
+
+	ip_discovery_packet(uint32_t _ssrc) :
+		type(htons(0x01)), length(htons(sizeof(ip_discovery_packet) - sizeof(type) - sizeof(length))),
+		ssrc(htonl(_ssrc)), port(0) {
+		std::memset(&address, 0, sizeof(address));
+	}
+};
+#pragma pack(pop)
+
+std::string discord_voice_client::discover_ip() {
+
+	if (!external_ip.empty()) {
+		return external_ip;
+	}
+
+	dpp::socket newfd = SOCKET_ERROR;
+	ip_discovery_packet discovery((uint32_t)this->ssrc);
+
+	if ((newfd = ::socket(AF_INET, SOCK_DGRAM, 0)) >= 0) {
+		sockaddr_in servaddr{};
+		memset(&servaddr, 0, sizeof(sockaddr_in));
+		servaddr.sin_family = AF_INET;
+		servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
+		servaddr.sin_port = htons(0);
+		if (bind(newfd, (sockaddr*)&servaddr, sizeof(servaddr)) < 0) {
+			log(ll_warning, "Could not bind socket for IP discovery");
+			return "";
+		}
+		memset(&servaddr, 0, sizeof(servaddr));
+		servaddr.sin_family = AF_INET;
+		servaddr.sin_port = htons(this->port);
+		servaddr.sin_addr.s_addr = inet_addr(this->ip.c_str());
+		if (::connect(newfd, (const sockaddr*)&servaddr, sizeof(sockaddr_in)) < 0) {
+			log(ll_warning, "Could not connect socket for IP discovery");
+			return "";
+		}
+		if (::send(newfd, reinterpret_cast<const char*>(&discovery), sizeof(discovery), 0) == -1) {
+			log(ll_warning, "Could not send packet for IP discovery");
+			return "";
+		}
+		if (recv(newfd, reinterpret_cast<char*>(&discovery), sizeof(discovery), 0) == -1) {
+			log(ll_warning, "Could not receive packet for IP discovery");
+			return "";
+		}
+
+		close_socket(newfd);
+
+		return {discovery.address, strlen(discovery.address)};
+	}
+	return {};
+}
+
+}

src/dpp/voice/stub/stubs.cpp

@@ -27,6 +27,12 @@
 
 namespace dpp {
 
+	discord_voice_client::discord_voice_client(dpp::cluster* _cluster, snowflake _channel_id, snowflake _server_id, const std::string &_token, const std::string &_session_id, const std::string &_host, bool enable_dave)
+		: websocket_client(_host.substr(0, _host.find(':')), _host.substr(_host.find(':') + 1, _host.length()), "/?v=" + std::to_string(voice_protocol_version), OP_TEXT)
+	{
+		throw dpp::voice_exception(err_no_voice_support, "Voice support not enabled in this build of D++");
+	}
+
 	void discord_voice_client::voice_courier_loop(discord_voice_client& client, courier_shared_state_t& shared_state) {
 	}
 
@@ -89,4 +95,8 @@ namespace dpp {
 		return 0;
 	}
 
+	std::string discord_voice_client::discover_ip() {
+		return "";
+	}
+
 }