refactor: modernize networking code with Boost.Asio

- Replace raw socket implementation with Boost.Asio in Proxy class
- Add proper SSL/TLS support using Boost.Asio SSL
- Improve error handling with more specific exceptions
- Modernize Utils class with C++17 features like string_view
- Refactor Windows service implementation with smart pointers and exception handling
- Enhance hostname resolution with Boost.Asio resolver

include/Proxy.h

@@ -3,19 +3,21 @@
 #include <string>
 #include <boost/asio.hpp>
 #include <boost/asio/ssl.hpp>
+#include "Socket.h"
 
 #define SMTP_STATE_WAIT_FOR_HELO 0
 #define SMTP_STATE_WAIT_FOR_MAILFROM 1
 #define SMTP_STATE_WAIT_FOR_RCPTTO 2
 #define SMTP_STATE_WAIT_FOR_DATA 3
 
-class Proxy
-{
+class Proxy {
 public:
     Proxy();
-    void run(boost::asio::ssl::stream<boost::asio::ip::tcp::socket>* outside, const std::string& peer_address);
+    void setOutside(Socket& socket);
+    void run(const std::string& peer_address);
 
 private:
-    boost::asio::io_service& io_service_;
+    boost::asio::io_context io_context_;
     boost::asio::ssl::context ssl_context;
+    Socket* outside_socket_;
 };

include/Utils.h

@@ -22,6 +22,7 @@
 
 #include "hermes.h"
 #include <string>
+#include <string_view>
 #include <sstream>
 #include <iostream>
 #include <dirent.h>
@@ -35,7 +36,9 @@
 #include "Database.h"
 #include "Socket.h"
 
-using namespace std;
+using std::string;
+using std::stringstream;
+using std::list;
 
 #ifdef WIN32
 #define sleep(x) Sleep(1000*(x))
@@ -52,37 +55,37 @@ class Utils
 {
   public:
     //string utilities
-    static string strtolower(string);
-    static string trim(string);
+    static string strtolower(std::string_view);
+    static string trim(std::string_view);
     static string inttostr(int);
     static string ulongtostr(unsigned long);
 
     //email-related utilities
-    static string getmail(string&);
-    static string getdomain(string&);
-    static string reverseip(string&);
+    static string getmail(const string&);
+    static string getdomain(const string&);
+    static string reverseip(const string&);
 
     //spam-related utilities (TODO: move to a different class)
-    static bool greylist(string,string&,string&,string&);
-    static bool listed_on_dns_lists(list<string>&,unsigned char,string&);
-    static bool whitelisted(string,string&);
-    static bool blacklisted(string,string&,string&);
+    static bool greylist(const string& dbfile, string& ip, string& p_from, string& p_to);
+    static bool listed_on_dns_lists(const list<string>& dns_domains, unsigned char percentage, const string& ip);
+    static bool whitelisted(const string& dbfile, string& ip);
+    static bool blacklisted(const string& dbfile, string& ip, string& to);
 
     #ifndef WIN32
     //posix-utils
-    static int usertouid(string);
-    static int grouptogid(string);
+    static int usertouid(const string& user);
+    static int grouptogid(const string& groupname);
     #endif //WIN32
 
     //misc
-    static string get_canonical_filename(string);
-    static bool file_exists(string);
-    static bool dir_exists(string);
+    static string get_canonical_filename(const string& file);
+    static bool file_exists(const string& file);
+    static bool dir_exists(const string& dir);
     static string errnotostrerror(int);
     static string rfc2821_date(time_t *timestamp=NULL);
     static string gethostname();
-    static void write_pid(string,pid_t);
-    static string gethostname(int s);
+    static void write_pid(const string& file, pid_t pid);
+    static string gethostname(int socket);
 };
 
 #endif //UTILS_H