SSL_read在第一次读取时返回-1

Question

问题：当我第一次调用bytes = SSL_read(ssl, buf, sizeof(buf));时，它总是返回-1，但是下一次调用会返回标题等。 你能帮我找一下我的错误吗？

1. 我创建了SSL对象
2. 致电请求

示例请求：

POST /some/page HTTP/1.1
Connection: keep-alive
Content-Type: text/html;charset=UTF-8
Host: example.com
Content-Length: 123 (just for ex.)

<mytag /> <mysecondtag />

创建SSL对象

  SSLConnection::SSLConnection(string _server, int _port)
{
  int err = 0;
  struct sockaddr_in address;
  X509* scert;
  char* txt;
  char buff[4096];
  SSL_METHOD *meth;
  WORD wVersionRequested;
  WSADATA wsaData;
  SSLeay_add_ssl_algorithms();
  meth = SSLv23_method();
  SSL_load_error_strings();
  ctx = SSL_CTX_new(meth);

  printf("ctx created\n");

  if (ctx == NULL) {
    bad_ = true;
    error_message_ = L"Context is NULL";
    return;
  }
  if (err == -1) {
    ERR_print_errors_fp(stdout);
    bad_ = true;
    return;
  }

  // Socket initialization and connection to the server.
  wVersionRequested = MAKEWORD(1, 1);
  err = WSAStartup(wVersionRequested, &wsaData);
  if (err != 0)
  {
    error_message_ = wprintf_s(L"///eRROR EN WSASstartup//%d\n", err);
    bad_ = true;
    return;
  }

  sd = socket(AF_INET, SOCK_STREAM, 0);
  if (sd == -1) {
    bad_ = true;
    error_message_ = L"Socket not initialized";
    return;
  }

  memset(&address, '\0', sizeof(address));
  address.sin_family = AF_INET;
  address.sin_addr.s_addr = inet_addr(_server.c_str());
  address.sin_port = htons(_port);
  address.sin_addr.S_un.S_addr = inet_addr(_server.c_str());

  err = connect(sd, (struct sockaddr*) &address, sizeof(address));
  if (err == -1) {
    bad_ = true;
    error_message_ = L"Connection not created";
    return;
  }

  // We started the SSL negotiation
  ssl = SSL_new(ctx);
  if (ssl == NULL) {
    bad_ = true;
    error_message_ = L"SSL not created";
    return;
  }
  SSL_set_fd(ssl, sd);



  // Setting client certificate and key
  int res = 0;
  res = SSL_use_certificate_file(ssl, "path1", SSL_FILETYPE_PEM);
  printf("Cert assigned: %d\n", res);
  if (res <= 0) {
    ERR_print_errors_fp(stdout);
    bad_ = true;
    return;
  }
  res = SSL_use_PrivateKey_file(ssl, "path2", SSL_FILETYPE_PEM);
  printf("Key assigned: %d\n", res);
  if (res <= 0) {
    ERR_print_errors_fp(stdout);
    bad_ = true;
    return;
  }
  err = SSL_connect(ssl);
  if (err == -1) {
    ERR_print_errors_fp(stdout);
    bad_ = true;
    return;
  } else printf("SSL Connection established\n");

  if (!SSL_CTX_check_private_key(ctx)) {
    printf("private key is not valid\r");
  }

  /* The next two steps are optional */

  /* We get the cipher - optional */
  // TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384
  printf("SSL connection using %s\n", SSL_get_cipher(ssl));
  cipher = SSL_get_cipher(ssl);

  /* We get the Server certificate - optional */
  scert = SSL_get_peer_certificate(ssl);
  CHK_NULL(scert);

  txt = X509_NAME_oneline(X509_get_subject_name(scert), 0, 0);
  CHK_NULL(txt);
  cert_subject = txt;
  OPENSSL_free(txt);

  txt = X509_NAME_oneline(X509_get_issuer_name(scert), 0, 0);
  CHK_NULL(txt);
  cert_issuer = txt;
  OPENSSL_free(txt);

  X509_free(scert);
}

请求方法

int SSLConnection::request(const char *_request, 
                       map<char *, char *> &_response_headers,
                       string &_response_body) {
    if (bad_) { 
      bad_ = true;
      error_message_ = L"There is no connection"; 
      return -2; 
    }

    // Sending request
    printf("Sending request\n");
    char buf[100000];
    int bytes;
    string _tmp_response;
    SSL_write(ssl, _request, strlen(_request));

    // Reading response
    printf("Reading response\n");
    int response_size = 0;
    bool flag = 0;
    int error_count = 0;
    while (true) {
      Sleep(1000);
      bytes = SSL_read(ssl, buf, sizeof(buf));
      printf("Bytes: %d\n", bytes);
      if (bytes < 0) {
        error_count++;
        if (error_count > 3) {
          bad_ = true;
          error_message_ = L"SSL_read: something went wrong!";
          printf("SSL_read: something went wrong!\n");
          return -1;
        }
      }
      if (bytes == 0) break;
      printf("--------- Response (%d)---------\n", bytes);
      for (int i = 0; i<bytes; ++i) printf("%c", buf[i]);
      printf("\n--------- End response ---------\n");
      //if (!flag) flag = 1;
      //else {
        for (int i = 0; i<bytes; ++i)
          _tmp_response += buf[i];
        response_size += bytes;
      //}
      buf[0] = 0;
    }
    _tmp_response.resize(response_size);

    closesocket(sd);
    SSL_free(ssl);
    SSL_CTX_free(ctx);
    return 1;
  }