Support the ident protocol

fix #3211

louloulibs/network/tcp_server_socket.hpp

@@ -0,0 +1,86 @@
+#pragma once
+
+#include <network/socket_handler.hpp>
+#include <network/resolver.hpp>
+#include <network/poller.hpp>
+
+#include <string>
+
+#include <arpa/inet.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/ip.h>
+
+#include <logger/logger.hpp>
+
+#include <cstring>
+#include <cassert>
+
+using namespace std::string_literals;
+
+template <typename RemoteSocketType>
+class TcpSocketServer: public SocketHandler
+{
+ public:
+  TcpSocketServer(std::shared_ptr<Poller> poller, const uint16_t port):
+      SocketHandler(poller, -1)
+  {
+    if ((this->socket = ::socket(AF_INET6, SOCK_STREAM, 0)) == -1)
+      throw std::runtime_error("Could not create socket: "s + std::strerror(errno));
+
+    int opt = 1;
+    if (::setsockopt(this->socket, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt)) == -1)
+      throw std::runtime_error("Failed to set socket option: "s + std::strerror(errno));
+
+    struct sockaddr_in6 addr{};
+    addr.sin6_family = AF_INET6;
+    addr.sin6_port = htons(port);
+    addr.sin6_addr = IN6ADDR_ANY_INIT;
+    if ((::bind(this->socket, (const struct sockaddr*)&addr, sizeof(addr))) == -1)
+      { // If we can’t listen on this port, we just give up, but this is not fatal.
+        log_warning("Failed to bind on port ", std::to_string(port), ": ", std::strerror(errno));
+        return;
+      }
+
+    if ((::listen(this->socket, 10)) == -1)
+      throw std::runtime_error("listen() failed");
+
+    this->accept();
+  }
+  ~TcpSocketServer() = default;
+
+  void on_recv() override
+  {
+    // Accept a RemoteSocketType
+    int socket = ::accept(this->socket, nullptr, nullptr);
+
+    auto client = std::make_unique<RemoteSocketType>(poller, socket, *this);
+    this->poller->add_socket_handler(client.get());
+    this->sockets.push_back(std::move(client));
+  }
+
+ protected:
+  std::vector<std::unique_ptr<RemoteSocketType>> sockets;
+
+ private:
+  void accept()
+  {
+    this->poller->add_socket_handler(this);
+  }
+  void on_send() override
+  {
+    assert(false);
+  }
+  void connect() override
+  {
+    assert(false);
+  }
+  bool is_connected() const override
+  {
+    return true;
+  }
+  bool is_connecting() const override
+  {
+    return false;
+  }
+};