Preserve transport errors for OpenSSL sockets.

net/socket/openssl_ssl_util.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/socket/openssl_ssl_util.h"
 
 #include <openssl/err.h>
 #include <openssl/ssl.h>
 
 #include "base/logging.h"
@@ skipping 128 matching lines @@
     case SSL_ERROR_WANT_READ:
     case SSL_ERROR_WANT_WRITE:
       return ERR_IO_PENDING;
     case SSL_ERROR_SYSCALL:
       LOG(ERROR) << "OpenSSL SYSCALL error, earliest error code in "
                     "error queue: " << ERR_peek_error() << ", errno: "
                  << errno;
       return ERR_SSL_PROTOCOL_ERROR;
     case SSL_ERROR_SSL:
       return MapOpenSSLErrorSSL();
+    case SSL_ERROR_ZERO_RETURN:
+      return 0;
     default:
       // TODO(joth): Implement full mapping.
       LOG(WARNING) << "Unknown OpenSSL error " << err;
       return ERR_SSL_PROTOCOL_ERROR;
   }
 }
 
 }  // namespace net