[Server] Configuration Issues Checker (LAN Detection) (#2283)

* LAN detect

* Add more checks, consolidate logic

* Tweaks

* Tweaks

* Update world_config.cpp

* Tweak logic

* Add DNS resolution

* Delete task runner after being used

* JSON path notation adjust

common/ip_util.cpp

@@ -18,7 +18,23 @@
  *
  */
 
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <unistd.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <fmt/format.h>
+#include <csignal>
+#include <vector>
 #include "ip_util.h"
+#include "http/httplib.h"
+#include "http/uri.h"
+#include "eqemu_logsys.h"
+#include "event/event_loop.h"
+#include "net/dns.h"
+#include "event/task_scheduler.h"
 
 /**
  * @param ip
@@ -70,3 +86,148 @@ bool IpUtil::IsIpInPrivateRfc1918(const std::string &ip)
 		IpUtil::IsIpInRange(ip, "192.168.0.0", "255.255.0.0")
 	);
 }
+
+/**
+ * Gets local address - pings google to inspect what interface was used locally
+ * @return
+ */
+std::string IpUtil::GetLocalIPAddress()
+{
+	char               my_ip_address[16];
+	unsigned int       my_port;
+	struct sockaddr_in server_address{};
+	struct sockaddr_in my_address{};
+	int                sockfd;
+
+	// Connect to server
+	if ((sockfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
+		return "";
+	}
+
+	// Set server_addr
+	bzero(&server_address, sizeof(server_address));
+	server_address.sin_family      = AF_INET;
+	server_address.sin_addr.s_addr = inet_addr("172.217.160.99");
+	server_address.sin_port        = htons(80);
+
+	// Connect to server
+	if (connect(sockfd, (struct sockaddr *) &server_address, sizeof(server_address)) < 0) {
+		close(sockfd);
+		return "";
+	}
+
+	// Get my ip address and port
+	bzero(&my_address, sizeof(my_address));
+	socklen_t len = sizeof(my_address);
+	getsockname(sockfd, (struct sockaddr *) &my_address, &len);
+	inet_ntop(AF_INET, &my_address.sin_addr, my_ip_address, sizeof(my_ip_address));
+	my_port = ntohs(my_address.sin_port);
+
+	return fmt::format("{}", my_ip_address);
+}
+
+/**
+ * Gets public address
+ * Uses various websites as options to return raw public IP back to the client
+ * @return
+ */
+std::string IpUtil::GetPublicIPAddress()
+{
+	std::vector<std::string> endpoints = {
+		"http://ifconfig.me",
+		"http://api.ipify.org",
+		"http://ipinfo.io/ip",
+		"http://ipecho.net/plain",
+	};
+
+	for (auto &s: endpoints) {
+		// http get request
+		uri u(s);
+
+		httplib::Client r(
+			fmt::format(
+				"{}://{}",
+				u.get_scheme(),
+				u.get_host()
+			).c_str()
+		);
+
+		httplib::Headers headers = {
+			{"Content-type", "text/plain; charset=utf-8"},
+			{"User-Agent",   "curl/7.81.0"}
+		};
+
+		r.set_connection_timeout(1, 0);
+		r.set_read_timeout(1, 0);
+		r.set_write_timeout(1, 0);
+
+		if (auto res = r.Get(fmt::format("/{}", u.get_path()).c_str(), headers)) {
+			if (res->status == 200) {
+				if (res->body.find('.') != std::string::npos) {
+					return res->body;
+				}
+			}
+		}
+	}
+
+	return {};
+}
+
+std::string IpUtil::DNSLookupSync(const std::string &addr, int port)
+{
+	auto task_runner = new EQ::Event::TaskScheduler();
+	auto res         = task_runner->Enqueue(
+		[&]() -> std::string {
+			bool        running = true;
+			std::string ret;
+
+			EQ::Net::DNSLookup(
+				addr, port, false, [&](const std::string &addr) {
+					ret = addr;
+					if (addr.empty()) {
+						ret     = "";
+						running = false;
+					}
+
+					return ret;
+				}
+			);
+
+			std::chrono::steady_clock::time_point begin = std::chrono::steady_clock::now();
+
+			auto &loop = EQ::EventLoop::Get();
+			while (running) {
+				if (!ret.empty()) {
+					running = false;
+				}
+
+				std::chrono::steady_clock::time_point end = std::chrono::steady_clock::now();
+				if (std::chrono::duration_cast<std::chrono::milliseconds>(end - begin).count() > 1500) {
+					LogInfo(
+						"[DNSLookupSync] Deadline exceeded [{}]",
+						1500
+					);
+					running = false;
+				}
+
+				loop.Process();
+			}
+
+			return ret;
+		}
+	);
+
+	std::string result = res.get();
+	safe_delete(task_runner);
+
+	return result;
+}
+
+bool IpUtil::IsIPAddress(const std::string &ip_address)
+{
+	struct sockaddr_in sa{};
+	int                result = inet_pton(AF_INET, ip_address.c_str(), &(sa.sin_addr));
+	return result != 0;
+}
+
+