Prepare files for public release

include/util/ip.h

@@ -0,0 +1,24 @@
+#ifndef IP_UTIL_H
+#define IP_UTIL_H
+
+#ifdef _WIN32
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#define CLOSE_SOCKET closesocket
+#pragma comment(lib, "ws2_32.lib")
+typedef SOCKET socket_t;
+#else
+#include <arpa/inet.h>
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#define CLOSE_SOCKET close
+typedef int socket_t;
+#endif
+
+bool is_valid_ipv4(const std::string &ip) {
+    struct in_addr addr;
+    return inet_pton(AF_INET, ip.c_str(), &addr) == 1;
+}
+
+#endif // IP_UTIL_H