switch to coroutine execution model

src/DNSServer.hh

@@ -1,7 +1,6 @@
 #pragma once
 
-#include <event2/event.h>
-
+#include <asio.hpp>
 #include <memory>
 #include <set>
 #include <string>
@@ -9,36 +8,25 @@
 
 #include "IPV4RangeSet.hh"
 
+struct ServerState;
+
 class DNSServer {
 public:
-  DNSServer(
-      std::shared_ptr<struct event_base> base,
-      uint32_t local_connect_address,
-      uint32_t external_connect_address,
-      std::shared_ptr<const IPV4RangeSet> banned_ipv4_ranges);
+  explicit DNSServer(std::shared_ptr<ServerState> state);
   DNSServer(const DNSServer&) = delete;
   DNSServer(DNSServer&&) = delete;
-  virtual ~DNSServer();
+  DNSServer& operator=(const DNSServer&) = delete;
+  DNSServer& operator=(DNSServer&&) = delete;
+  virtual ~DNSServer() = default;
 
-  inline void set_banned_ipv4_ranges(std::shared_ptr<const IPV4RangeSet> banned_ipv4_ranges) {
-    this->banned_ipv4_ranges = banned_ipv4_ranges;
-  }
-
-  void listen(const std::string& socket_path);
   void listen(const std::string& addr, int port);
-  void listen(int port);
-  void add_socket(int fd);
 
   static std::string response_for_query(const void* vdata, size_t size, uint32_t resolved_address);
   static std::string response_for_query(const std::string& query, uint32_t resolved_address);
 
 private:
-  std::shared_ptr<struct event_base> base;
-  std::unordered_map<int, std::unique_ptr<struct event, void (*)(struct event*)>> fd_to_receive_event;
-  uint32_t local_connect_address;
-  uint32_t external_connect_address;
-  std::shared_ptr<const IPV4RangeSet> banned_ipv4_ranges;
+  std::shared_ptr<ServerState> state;
+  std::unordered_set<std::shared_ptr<asio::ip::udp::socket>> sockets;
 
-  static void dispatch_on_receive_message(evutil_socket_t fd, short events, void* ctx);
-  void on_receive_message(int fd, short event);
+  asio::awaitable<void> dns_server_task(std::shared_ptr<asio::ip::udp::socket> sock);
 };