[Unit]
Description=server service
After=network.target

[Service]
ExecStart=/home/dima/Загрузки/Сервер/server
ExecStop=/home/dima/Загрузки/Сервер/server
Restart=always


[Install]
WantedBy=multi-user.target

#include <iostream>
#include <sys/types.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netdb.h>
#include <arpa/inet.h>
#include <string.h>
#include <string>
 
using namespace std;
 
int main()
{
    // Create a socket
    int listening = socket(AF_INET, SOCK_STREAM, 0);
    if (listening == -1)
    {
        cerr << "Can't create a socket! Quitting" << endl;
        return -1;
    }
 
    // Bind the ip address and port to a socket
    sockaddr_in server;
    server.sin_family = AF_INET;
    server.sin_port = htons(1234);
    inet_pton(AF_INET, "0.0.0.0", &server.sin_addr);
 
    bind(listening, (sockaddr*)&server, sizeof(server));
 
    // Tell Winsock the socket is for listening
    listen(listening, SOMAXCONN);
 
    // Wait for a connection
    sockaddr_in client;
    socklen_t clientSize = sizeof(client);
 
    int clientSocket = accept(listening, (sockaddr*)&client, &clientSize);
 
    char host[NI_MAXHOST];      // Client's remote name
    char service[NI_MAXSERV];   // Service (i.e. port) the client is connect on
 
    memset(host, 0, NI_MAXHOST); // same as memset(host, 0, NI_MAXHOST);
    memset(service, 0, NI_MAXSERV);
 
    if (getnameinfo((sockaddr*)&client, sizeof(client), host, NI_MAXHOST, service, NI_MAXSERV, 0) == 0)
    {
        cout << host << " connected on port " << service << endl;
    }
    else
    {
        inet_ntop(AF_INET, &client.sin_addr, host, NI_MAXHOST);
        cout << host << " connected on port " << ntohs(client.sin_port) << endl;
    }
 
    // Close listening socket
    close(listening);
 
    // While loop: accept and echo message back to client
    char buf[4096];
 
    while (true)
    {
        memset(buf, 0, 4096);
 
        // Wait for client to send data
        int bytesReceived = recv(clientSocket, buf, 4096, 0);
        if (bytesReceived == -1)
        {
            cerr << "Error in recv(). Quitting" << endl;
            break;
        }
 
        if (bytesReceived == 0)
        {
            cout << "Client disconnected " << endl;
            break;
        }
 
        cout << string(buf, 0, bytesReceived) << endl;
 
        // Echo message back to client
        send(clientSocket, buf, bytesReceived + 1, 0);
    }
 
    // Close the socket
      close(clientSocket);
   
 
    return 0;
}