Многопоточный сервер

#include <iostream>
 
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include <errno.h>
#include <sys/types.h>
 
 
#ifndef WIN32
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#else
#include <io.h>
#include <Winsock2.h>
#pragma comment(lib, "ws2_32.lib")
#endif
 
#include <openssl/rsa.h>
#include <openssl/rsa.h>
#include <openssl/crypto.h>
#include <openssl/x509.h>
#include <openssl/pem.h>
#include <openssl/ssl.h>
#include <openssl/err.h>
 
/* define HOME to be dir for key and cert files... */
#define HOME "./"
/* Make these what you want for cert & key files */
#define CERTF  HOME "ca-cert.pem"
#define KEYF  HOME  "ca-cert.pem"
 
#define CHK_NULL(x) if ((x)==NULL) exit (1)
#define CHK_ERR(err,s) if ((err)==-1) { perror(s); exit(1); }
#define CHK_SSL(err) if ((err)==-1) { ERR_print_errors_fp(stderr); exit(2); }
 
#ifdef WIN32
const SSL_METHOD *meth = SSLv23_method();
#else
SSL_METHOD *meth = SSLv23_server_method();
#endif
 
int main()
{
    int err;
    int listen_sd;
    int sd;
    struct sockaddr_in sa_serv;
    struct sockaddr_in sa_cli;
    size_t client_len;
    SSL_CTX* ctx;
    SSL*     ssl;
    X509*    client_cert;
    char*    str;
    char     buf[4096];
    //SSL_METHOD *meth;
 
#ifdef WIN32
    WSADATA wsaData;
    if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
    {
        printf("Could not to find usable WinSock in WSAStartup\n");
        return 0;
    }
#endif
 
    /* SSL preliminaries. We keep the certificate and key with the context. */
 
    SSL_load_error_strings();
    SSLeay_add_ssl_algorithms();
    meth = SSLv23_server_method();
    ctx = SSL_CTX_new(meth);
    if (!ctx) {
        ERR_print_errors_fp(stderr);
        exit(2);
    }
 
    if (SSL_CTX_use_certificate_file(ctx, CERTF, SSL_FILETYPE_PEM) <= 0) {
        ERR_print_errors_fp(stderr);
        exit(3);
    }
    if (SSL_CTX_use_PrivateKey_file(ctx, KEYF, SSL_FILETYPE_PEM) <= 0) {
        ERR_print_errors_fp(stderr);
        exit(4);
    }
 
    if (!SSL_CTX_check_private_key(ctx)) {
        fprintf(stderr, "Private key does not match the certificate public key\n");
        exit(5);
    }
 
    /* ----------------------------------------------- */
    /* Prepare TCP socket for receiving connections */
 
    listen_sd = socket(AF_INET, SOCK_STREAM, 0);   CHK_ERR(listen_sd, "socket");
 
    memset(&sa_serv, '\0', sizeof(sa_serv));
    sa_serv.sin_family = AF_INET;
    sa_serv.sin_addr.s_addr = INADDR_ANY;
    sa_serv.sin_port = htons(1111);          /* Server Port number */
 
    err = bind(listen_sd, (struct sockaddr*) &sa_serv,
        sizeof(sa_serv));                   CHK_ERR(err, "bind");
 
    /* Receive a TCP connection. */
 
    err = listen(listen_sd, 5);                    CHK_ERR(err, "listen");
 
    client_len = sizeof(sa_cli);
    //sd = accept(listen_sd, (struct sockaddr*) &sa_cli, &client_len);
#ifdef WIN32
    sd = accept(listen_sd, (struct sockaddr*) &sa_cli, (int *)&client_len);
#else
    sd = accept(listen_sd, (struct sockaddr*) &sa_cli, &client_len);
#endif
 
    CHK_ERR(sd, "accept");
    closesocket(listen_sd);
 
    printf("Connection from %lx, port %x\n",
        sa_cli.sin_addr.s_addr, sa_cli.sin_port);
 
    /* ----------------------------------------------- */
    /* TCP connection is ready. Do server side SSL. */
 
    ssl = SSL_new(ctx);                           CHK_NULL(ssl);
    SSL_set_fd(ssl, sd);
    err = SSL_accept(ssl);                        CHK_SSL(err);
 
    printf("ACCEPT...\n");
 
    /* Get the cipher - opt */
 
    printf("SSL connection using %s\n", SSL_get_cipher(ssl));
 
    /* DATA EXCHANGE - Receive message and send reply. */
 
    err = SSL_read(ssl, buf, sizeof(buf) - 1);                   CHK_SSL(err);
    buf[err] = '\0';
    printf("Got %d chars:'%s'\n", err, buf);
 
    err = SSL_write(ssl, "I hear you.", strlen("I hear you."));  CHK_SSL(err);
 
    /* Clean up. */
 
    closesocket(sd);
    SSL_free(ssl);
    SSL_CTX_free(ctx);
 
 
    system("pause");
    return 0;
}