osci-render/Source/ixwebsocket/IXSocketOpenSSL.cpp

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28 KiB
C++

/*
* IXSocketOpenSSL.cpp
* Author: Benjamin Sergeant, Matt DeBoer, Max Weisel
* Copyright (c) 2017-2020 Machine Zone, Inc. All rights reserved.
*
* Adapted from Satori SDK OpenSSL code.
*/
#ifdef IXWEBSOCKET_USE_OPEN_SSL
#include "IXSocketOpenSSL.h"
#include "IXSocketConnect.h"
#include "IXUniquePtr.h"
#include <cassert>
#include <errno.h>
#include <vector>
#ifdef _WIN32
#include <shlwapi.h>
#else
#include <fnmatch.h>
#endif
#if OPENSSL_VERSION_NUMBER < 0x10100000L
#include <openssl/x509v3.h>
#endif
#define socketerrno errno
#ifdef _WIN32
// For manipulating the certificate store
#include <wincrypt.h>
#endif
#ifdef _WIN32
namespace
{
bool loadWindowsSystemCertificates(SSL_CTX* ssl, std::string& errorMsg)
{
DWORD flags = CERT_STORE_READONLY_FLAG | CERT_STORE_OPEN_EXISTING_FLAG |
CERT_SYSTEM_STORE_CURRENT_USER;
HCERTSTORE systemStore = CertOpenStore(CERT_STORE_PROV_SYSTEM, 0, 0, flags, L"Root");
if (!systemStore)
{
errorMsg = "CertOpenStore failed with ";
errorMsg += std::to_string(GetLastError());
return false;
}
PCCERT_CONTEXT certificateIterator = NULL;
X509_STORE* opensslStore = SSL_CTX_get_cert_store(ssl);
int certificateCount = 0;
while (certificateIterator = CertEnumCertificatesInStore(systemStore, certificateIterator))
{
X509* x509 = d2i_X509(NULL,
(const unsigned char**) &certificateIterator->pbCertEncoded,
certificateIterator->cbCertEncoded);
if (x509)
{
if (X509_STORE_add_cert(opensslStore, x509) == 1)
{
++certificateCount;
}
X509_free(x509);
}
}
CertFreeCertificateContext(certificateIterator);
CertCloseStore(systemStore, 0);
if (certificateCount == 0)
{
errorMsg = "No certificates found";
return false;
}
return true;
}
} // namespace
#endif
namespace ix
{
const std::string kDefaultCiphers =
"ECDHE-ECDSA-AES128-GCM-SHA256 ECDHE-ECDSA-AES256-GCM-SHA384 ECDHE-ECDSA-AES128-SHA "
"ECDHE-ECDSA-AES256-SHA ECDHE-ECDSA-AES128-SHA256 ECDHE-ECDSA-AES256-SHA384 "
"ECDHE-RSA-AES128-GCM-SHA256 ECDHE-RSA-AES256-GCM-SHA384 ECDHE-RSA-AES128-SHA "
"ECDHE-RSA-AES256-SHA ECDHE-RSA-AES128-SHA256 ECDHE-RSA-AES256-SHA384 "
"DHE-RSA-AES128-GCM-SHA256 DHE-RSA-AES256-GCM-SHA384 DHE-RSA-AES128-SHA "
"DHE-RSA-AES256-SHA DHE-RSA-AES128-SHA256 DHE-RSA-AES256-SHA256 AES128-SHA";
std::atomic<bool> SocketOpenSSL::_openSSLInitializationSuccessful(false);
std::once_flag SocketOpenSSL::_openSSLInitFlag;
std::vector<std::unique_ptr<std::mutex>> openSSLMutexes;
SocketOpenSSL::SocketOpenSSL(const SocketTLSOptions& tlsOptions, int fd)
: Socket(fd)
, _ssl_connection(nullptr)
, _ssl_context(nullptr)
, _tlsOptions(tlsOptions)
{
std::call_once(_openSSLInitFlag, &SocketOpenSSL::openSSLInitialize, this);
}
SocketOpenSSL::~SocketOpenSSL()
{
SocketOpenSSL::close();
}
void SocketOpenSSL::openSSLInitialize()
{
#if OPENSSL_VERSION_NUMBER >= 0x10100000L
if (!OPENSSL_init_ssl(OPENSSL_INIT_LOAD_CONFIG, nullptr)) return;
#else
(void) OPENSSL_config(nullptr);
if (CRYPTO_get_locking_callback() == nullptr)
{
openSSLMutexes.clear();
for (int i = 0; i < CRYPTO_num_locks(); ++i)
{
openSSLMutexes.push_back(ix::make_unique<std::mutex>());
}
CRYPTO_set_locking_callback(SocketOpenSSL::openSSLLockingCallback);
}
#endif
(void) OpenSSL_add_ssl_algorithms();
(void) SSL_load_error_strings();
_openSSLInitializationSuccessful = true;
}
void SocketOpenSSL::openSSLLockingCallback(int mode,
int type,
const char* /*file*/,
int /*line*/)
{
if (mode & CRYPTO_LOCK)
{
openSSLMutexes[type]->lock();
}
else
{
openSSLMutexes[type]->unlock();
}
}
std::string SocketOpenSSL::getSSLError(int ret)
{
unsigned long e;
int err = SSL_get_error(_ssl_connection, ret);
if (err == SSL_ERROR_WANT_CONNECT || err == SSL_ERROR_WANT_ACCEPT)
{
return "OpenSSL failed - connection failure";
}
else if (err == SSL_ERROR_WANT_X509_LOOKUP)
{
return "OpenSSL failed - x509 error";
}
else if (err == SSL_ERROR_SYSCALL)
{
e = ERR_get_error();
if (e > 0)
{
std::string errMsg("OpenSSL failed - ");
errMsg += ERR_error_string(e, nullptr);
return errMsg;
}
else if (e == 0 && ret == 0)
{
return "OpenSSL failed - received early EOF";
}
else
{
return "OpenSSL failed - underlying BIO reported an I/O error";
}
}
else if (err == SSL_ERROR_SSL)
{
e = ERR_get_error();
std::string errMsg("OpenSSL failed - ");
errMsg += ERR_error_string(e, nullptr);
return errMsg;
}
else if (err == SSL_ERROR_NONE)
{
return "OpenSSL failed - err none";
}
else if (err == SSL_ERROR_ZERO_RETURN)
{
return "OpenSSL failed - err zero return";
}
else
{
return "OpenSSL failed - unknown error";
}
}
SSL_CTX* SocketOpenSSL::openSSLCreateContext(std::string& errMsg)
{
const SSL_METHOD* method = SSLv23_client_method();
if (method == nullptr)
{
errMsg = "SSLv23_client_method failure";
return nullptr;
}
_ssl_method = method;
SSL_CTX* ctx = SSL_CTX_new(_ssl_method);
if (ctx)
{
SSL_CTX_set_mode(ctx,
SSL_MODE_ENABLE_PARTIAL_WRITE | SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
int options = SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3 | SSL_OP_CIPHER_SERVER_PREFERENCE;
#ifdef SSL_OP_NO_TLSv1_3
// (partially?) work around hang in openssl 1.1.1b, by disabling TLS V1.3
// https://github.com/openssl/openssl/issues/7967
options |= SSL_OP_NO_TLSv1_3;
#endif
SSL_CTX_set_options(ctx, options);
}
return ctx;
}
bool SocketOpenSSL::openSSLAddCARootsFromString(const std::string roots)
{
// Create certificate store
X509_STORE* certificate_store = SSL_CTX_get_cert_store(_ssl_context);
if (certificate_store == nullptr) return false;
// Configure to allow intermediate certs
X509_STORE_set_flags(certificate_store,
X509_V_FLAG_TRUSTED_FIRST | X509_V_FLAG_PARTIAL_CHAIN);
// Create a new buffer and populate it with the roots
BIO* buffer = BIO_new_mem_buf((void*) roots.c_str(), static_cast<int>(roots.length()));
if (buffer == nullptr) return false;
// Read each root in the buffer and add to the certificate store
bool success = true;
size_t number_of_roots = 0;
while (true)
{
// Read the next root in the buffer
X509* root = PEM_read_bio_X509_AUX(buffer, nullptr, nullptr, (void*) "");
if (root == nullptr)
{
// No more certs left in the buffer, we're done.
ERR_clear_error();
break;
}
// Try adding the root to the certificate store
ERR_clear_error();
if (!X509_STORE_add_cert(certificate_store, root))
{
// Failed to add. If the error is unrelated to the x509 lib or the cert already
// exists, we're safe to continue.
unsigned long error = ERR_get_error();
if (ERR_GET_LIB(error) != ERR_LIB_X509 ||
ERR_GET_REASON(error) != X509_R_CERT_ALREADY_IN_HASH_TABLE)
{
// Failed. Clean up and bail.
success = false;
X509_free(root);
break;
}
}
// Clean up and loop
X509_free(root);
number_of_roots++;
}
// Clean up buffer
BIO_free(buffer);
// Make sure we loaded at least one certificate.
if (number_of_roots == 0) success = false;
return success;
}
/**
* Check whether a hostname matches a pattern
*/
bool SocketOpenSSL::checkHost(const std::string& host, const char* pattern)
{
#ifdef _WIN32
return PathMatchSpecA(host.c_str(), pattern);
#else
return fnmatch(pattern, host.c_str(), 0) != FNM_NOMATCH;
#endif
}
bool SocketOpenSSL::openSSLCheckServerCert(SSL* ssl,
#if OPENSSL_VERSION_NUMBER < 0x10100000L
const std::string& hostname,
#else
const std::string& /* hostname */,
#endif
std::string& errMsg)
{
X509* server_cert = SSL_get_peer_certificate(ssl);
if (server_cert == nullptr)
{
errMsg = "OpenSSL failed - peer didn't present a X509 certificate.";
return false;
}
#if OPENSSL_VERSION_NUMBER < 0x10100000L
// Check server name
bool hostname_verifies_ok = false;
STACK_OF(GENERAL_NAME)* san_names = (STACK_OF(GENERAL_NAME)*) X509_get_ext_d2i(
(X509*) server_cert, NID_subject_alt_name, NULL, NULL);
if (san_names)
{
for (int i = 0; i < sk_GENERAL_NAME_num(san_names); i++)
{
const GENERAL_NAME* sk_name = sk_GENERAL_NAME_value(san_names, i);
if (sk_name->type == GEN_DNS)
{
char* name = (char*) ASN1_STRING_data(sk_name->d.dNSName);
if ((size_t) ASN1_STRING_length(sk_name->d.dNSName) == strlen(name) &&
checkHost(hostname, name))
{
hostname_verifies_ok = true;
break;
}
}
}
}
sk_GENERAL_NAME_pop_free(san_names, GENERAL_NAME_free);
if (!hostname_verifies_ok)
{
int cn_pos = X509_NAME_get_index_by_NID(
X509_get_subject_name((X509*) server_cert), NID_commonName, -1);
if (cn_pos >= 0)
{
X509_NAME_ENTRY* cn_entry =
X509_NAME_get_entry(X509_get_subject_name((X509*) server_cert), cn_pos);
if (cn_entry != nullptr)
{
ASN1_STRING* cn_asn1 = X509_NAME_ENTRY_get_data(cn_entry);
char* cn = (char*) ASN1_STRING_data(cn_asn1);
if ((size_t) ASN1_STRING_length(cn_asn1) == strlen(cn) &&
checkHost(hostname, cn))
{
hostname_verifies_ok = true;
}
}
}
}
if (!hostname_verifies_ok)
{
errMsg = "OpenSSL failed - certificate was issued for a different domain.";
return false;
}
#endif
X509_free(server_cert);
return true;
}
bool SocketOpenSSL::openSSLClientHandshake(const std::string& host,
std::string& errMsg,
const CancellationRequest& isCancellationRequested)
{
while (true)
{
if (_ssl_connection == nullptr || _ssl_context == nullptr)
{
return false;
}
if (isCancellationRequested())
{
errMsg = "Cancellation requested";
return false;
}
ERR_clear_error();
int connect_result = SSL_connect(_ssl_connection);
if (connect_result == 1)
{
if (_tlsOptions.disable_hostname_validation)
{
return true;
}
return openSSLCheckServerCert(_ssl_connection, host, errMsg);
}
int reason = SSL_get_error(_ssl_connection, connect_result);
bool rc = false;
if (reason == SSL_ERROR_WANT_READ || reason == SSL_ERROR_WANT_WRITE)
{
rc = true;
}
else
{
errMsg = getSSLError(connect_result);
rc = false;
}
if (!rc)
{
return false;
}
}
}
bool SocketOpenSSL::openSSLServerHandshake(std::string& errMsg)
{
while (true)
{
if (_ssl_connection == nullptr || _ssl_context == nullptr)
{
return false;
}
ERR_clear_error();
int accept_result = SSL_accept(_ssl_connection);
if (accept_result == 1)
{
return true;
}
int reason = SSL_get_error(_ssl_connection, accept_result);
bool rc = false;
if (reason == SSL_ERROR_WANT_READ || reason == SSL_ERROR_WANT_WRITE)
{
rc = true;
}
else
{
errMsg = getSSLError(accept_result);
rc = false;
}
if (!rc)
{
return false;
}
}
}
bool SocketOpenSSL::handleTLSOptions(std::string& errMsg)
{
ERR_clear_error();
if (_tlsOptions.hasCertAndKey())
{
if (SSL_CTX_use_certificate_chain_file(_ssl_context, _tlsOptions.certFile.c_str()) != 1)
{
auto sslErr = ERR_get_error();
errMsg = "OpenSSL failed - SSL_CTX_use_certificate_chain_file(\"" +
_tlsOptions.certFile + "\") failed: ";
errMsg += ERR_error_string(sslErr, nullptr);
}
else if (SSL_CTX_use_PrivateKey_file(
_ssl_context, _tlsOptions.keyFile.c_str(), SSL_FILETYPE_PEM) != 1)
{
auto sslErr = ERR_get_error();
errMsg = "OpenSSL failed - SSL_CTX_use_PrivateKey_file(\"" + _tlsOptions.keyFile +
"\") failed: ";
errMsg += ERR_error_string(sslErr, nullptr);
}
else if (!SSL_CTX_check_private_key(_ssl_context))
{
auto sslErr = ERR_get_error();
errMsg = "OpenSSL failed - cert/key mismatch(\"" + _tlsOptions.certFile + ", " +
_tlsOptions.keyFile + "\")";
errMsg += ERR_error_string(sslErr, nullptr);
}
}
ERR_clear_error();
if (!_tlsOptions.isPeerVerifyDisabled())
{
if (_tlsOptions.isUsingSystemDefaults())
{
#ifdef _WIN32
if (!loadWindowsSystemCertificates(_ssl_context, errMsg))
{
return false;
}
#else
if (SSL_CTX_set_default_verify_paths(_ssl_context) == 0)
{
auto sslErr = ERR_get_error();
errMsg = "OpenSSL failed - SSL_CTX_default_verify_paths loading failed: ";
errMsg += ERR_error_string(sslErr, nullptr);
return false;
}
#endif
}
else
{
if (_tlsOptions.isUsingInMemoryCAs())
{
// Load from memory
openSSLAddCARootsFromString(_tlsOptions.caFile);
}
else
{
if (SSL_CTX_load_verify_locations(
_ssl_context, _tlsOptions.caFile.c_str(), NULL) != 1)
{
auto sslErr = ERR_get_error();
errMsg = "OpenSSL failed - SSL_CTX_load_verify_locations(\"" +
_tlsOptions.caFile + "\") failed: ";
errMsg += ERR_error_string(sslErr, nullptr);
return false;
}
}
}
SSL_CTX_set_verify(_ssl_context,
SSL_VERIFY_PEER,
[](int preverify, X509_STORE_CTX*) -> int { return preverify; });
SSL_CTX_set_verify_depth(_ssl_context, 4);
}
else
{
SSL_CTX_set_verify(_ssl_context, SSL_VERIFY_NONE, nullptr);
}
if (_tlsOptions.isUsingDefaultCiphers())
{
if (SSL_CTX_set_cipher_list(_ssl_context, kDefaultCiphers.c_str()) != 1)
{
auto sslErr = ERR_get_error();
errMsg = "OpenSSL failed - SSL_CTX_set_cipher_list(\"" + kDefaultCiphers +
"\") failed: ";
errMsg += ERR_error_string(sslErr, nullptr);
return false;
}
}
else if (SSL_CTX_set_cipher_list(_ssl_context, _tlsOptions.ciphers.c_str()) != 1)
{
auto sslErr = ERR_get_error();
errMsg = "OpenSSL failed - SSL_CTX_set_cipher_list(\"" + _tlsOptions.ciphers +
"\") failed: ";
errMsg += ERR_error_string(sslErr, nullptr);
return false;
}
return true;
}
bool SocketOpenSSL::accept(std::string& errMsg)
{
bool handshakeSuccessful = false;
{
std::lock_guard<std::mutex> lock(_mutex);
if (!_openSSLInitializationSuccessful)
{
errMsg = "OPENSSL_init_ssl failure";
return false;
}
if (_sockfd == -1)
{
return false;
}
{
const SSL_METHOD* method = SSLv23_server_method();
if (method == nullptr)
{
errMsg = "SSLv23_server_method failure";
_ssl_context = nullptr;
}
else
{
_ssl_method = method;
_ssl_context = SSL_CTX_new(_ssl_method);
if (_ssl_context)
{
SSL_CTX_set_mode(_ssl_context, SSL_MODE_ENABLE_PARTIAL_WRITE);
SSL_CTX_set_mode(_ssl_context, SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER);
SSL_CTX_set_options(_ssl_context,
SSL_OP_ALL | SSL_OP_NO_SSLv2 | SSL_OP_NO_SSLv3);
}
}
}
if (_ssl_context == nullptr)
{
return false;
}
ERR_clear_error();
if (_tlsOptions.hasCertAndKey())
{
if (SSL_CTX_use_certificate_chain_file(_ssl_context,
_tlsOptions.certFile.c_str()) != 1)
{
auto sslErr = ERR_get_error();
errMsg = "OpenSSL failed - SSL_CTX_use_certificate_chain_file(\"" +
_tlsOptions.certFile + "\") failed: ";
errMsg += ERR_error_string(sslErr, nullptr);
}
else if (SSL_CTX_use_PrivateKey_file(
_ssl_context, _tlsOptions.keyFile.c_str(), SSL_FILETYPE_PEM) != 1)
{
auto sslErr = ERR_get_error();
errMsg = "OpenSSL failed - SSL_CTX_use_PrivateKey_file(\"" +
_tlsOptions.keyFile + "\") failed: ";
errMsg += ERR_error_string(sslErr, nullptr);
}
}
ERR_clear_error();
if (!_tlsOptions.isPeerVerifyDisabled())
{
if (_tlsOptions.isUsingSystemDefaults())
{
if (SSL_CTX_set_default_verify_paths(_ssl_context) == 0)
{
auto sslErr = ERR_get_error();
errMsg = "OpenSSL failed - SSL_CTX_default_verify_paths loading failed: ";
errMsg += ERR_error_string(sslErr, nullptr);
}
}
else
{
if (_tlsOptions.isUsingInMemoryCAs())
{
// Load from memory
openSSLAddCARootsFromString(_tlsOptions.caFile);
}
else
{
const char* root_ca_file = _tlsOptions.caFile.c_str();
STACK_OF(X509_NAME) * rootCAs;
rootCAs = SSL_load_client_CA_file(root_ca_file);
if (rootCAs == NULL)
{
auto sslErr = ERR_get_error();
errMsg = "OpenSSL failed - SSL_load_client_CA_file('" +
_tlsOptions.caFile + "') failed: ";
errMsg += ERR_error_string(sslErr, nullptr);
}
else
{
SSL_CTX_set_client_CA_list(_ssl_context, rootCAs);
if (SSL_CTX_load_verify_locations(
_ssl_context, root_ca_file, nullptr) != 1)
{
auto sslErr = ERR_get_error();
errMsg = "OpenSSL failed - SSL_CTX_load_verify_locations(\"" +
_tlsOptions.caFile + "\") failed: ";
errMsg += ERR_error_string(sslErr, nullptr);
}
}
}
}
SSL_CTX_set_verify(
_ssl_context, SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT, nullptr);
SSL_CTX_set_verify_depth(_ssl_context, 4);
}
else
{
SSL_CTX_set_verify(_ssl_context, SSL_VERIFY_NONE, nullptr);
}
if (_tlsOptions.isUsingDefaultCiphers())
{
if (SSL_CTX_set_cipher_list(_ssl_context, kDefaultCiphers.c_str()) != 1)
{
return false;
}
}
else if (SSL_CTX_set_cipher_list(_ssl_context, _tlsOptions.ciphers.c_str()) != 1)
{
return false;
}
_ssl_connection = SSL_new(_ssl_context);
if (_ssl_connection == nullptr)
{
errMsg = "OpenSSL failed to connect";
SSL_CTX_free(_ssl_context);
_ssl_context = nullptr;
return false;
}
SSL_set_ecdh_auto(_ssl_connection, 1);
SSL_set_fd(_ssl_connection, _sockfd);
handshakeSuccessful = openSSLServerHandshake(errMsg);
}
if (!handshakeSuccessful)
{
close();
return false;
}
return true;
}
bool SocketOpenSSL::connect(const std::string& host,
int port,
std::string& errMsg,
const CancellationRequest& isCancellationRequested)
{
bool handshakeSuccessful = false;
{
std::lock_guard<std::mutex> lock(_mutex);
if (!_openSSLInitializationSuccessful)
{
errMsg = "OPENSSL_init_ssl failure";
return false;
}
_sockfd = SocketConnect::connect(host, port, errMsg, isCancellationRequested);
if (_sockfd == -1) return false;
_ssl_context = openSSLCreateContext(errMsg);
if (_ssl_context == nullptr)
{
return false;
}
if (!handleTLSOptions(errMsg))
{
return false;
}
_ssl_connection = SSL_new(_ssl_context);
if (_ssl_connection == nullptr)
{
errMsg = "OpenSSL failed to connect";
SSL_CTX_free(_ssl_context);
_ssl_context = nullptr;
return false;
}
SSL_set_fd(_ssl_connection, _sockfd);
// SNI support
SSL_set_tlsext_host_name(_ssl_connection, host.c_str());
#if OPENSSL_VERSION_NUMBER >= 0x10002000L
// Support for server name verification
// (The docs say that this should work from 1.0.2, and is the default from
// 1.1.0, but it does not. To be on the safe side, the manual test
// below is enabled for all versions prior to 1.1.0.)
if (!_tlsOptions.disable_hostname_validation)
{
X509_VERIFY_PARAM* param = SSL_get0_param(_ssl_connection);
X509_VERIFY_PARAM_set1_host(param, host.c_str(), host.size());
}
#endif
handshakeSuccessful = openSSLClientHandshake(host, errMsg, isCancellationRequested);
}
if (!handshakeSuccessful)
{
close();
return false;
}
return true;
}
void SocketOpenSSL::close()
{
std::lock_guard<std::mutex> lock(_mutex);
if (_ssl_connection != nullptr)
{
SSL_free(_ssl_connection);
_ssl_connection = nullptr;
}
if (_ssl_context != nullptr)
{
SSL_CTX_free(_ssl_context);
_ssl_context = nullptr;
}
Socket::close();
}
ssize_t SocketOpenSSL::send(char* buf, size_t nbyte)
{
std::lock_guard<std::mutex> lock(_mutex);
if (_ssl_connection == nullptr || _ssl_context == nullptr)
{
return 0;
}
ERR_clear_error();
ssize_t write_result = SSL_write(_ssl_connection, buf, (int) nbyte);
int reason = SSL_get_error(_ssl_connection, (int) write_result);
if (reason == SSL_ERROR_NONE)
{
return write_result;
}
else if (reason == SSL_ERROR_WANT_READ || reason == SSL_ERROR_WANT_WRITE)
{
errno = EWOULDBLOCK;
return -1;
}
else
{
return -1;
}
}
ssize_t SocketOpenSSL::recv(void* buf, size_t nbyte)
{
while (true)
{
std::lock_guard<std::mutex> lock(_mutex);
if (_ssl_connection == nullptr || _ssl_context == nullptr)
{
return 0;
}
ERR_clear_error();
ssize_t read_result = SSL_read(_ssl_connection, buf, (int) nbyte);
if (read_result > 0)
{
return read_result;
}
int reason = SSL_get_error(_ssl_connection, (int) read_result);
if (reason == SSL_ERROR_WANT_READ || reason == SSL_ERROR_WANT_WRITE)
{
errno = EWOULDBLOCK;
}
return -1;
}
}
} // namespace ix
#endif // IXWEBSOCKET_USE_OPEN_SSL