Hi All, I have query regarding the SSL_read on blocking socket. How to come out of blocking SSL_read when we have to close the connection ?
As per the documentation SSL_read will only return if there is any data or an error occurred. "If the underlying BIO is *blocking*, SSL_read() will only return, *once the read operation has been finished or an error occurred,* except when a renegotiation take place, in which case a SSL_ERROR_WANT_READ may occur" I am trying following methods *method 1:* 1) Thread - 1 blocks in SSL_read 2) Thread - 2 receive indication to stop the connection from application. Call SSL_Shutdown() to unblock the SSL_read in thread - 1. But this is dangerous as calling SSL_shutdown and SSL_read from different threads on same context can lead to undefined behaviour. *method 2:* 1) Thread - 1 blocks in SSL_read 2) Thread - 2 receive indication to stop the connection from application. shutdown the underlying TCP socket using system command (shutdown (socket_id, SHUT_WR)) that cause the SSL_read to unblock. 3) Thread - 1 unwind and close the TCP socket (using close(socket_id)). thread -1 cannot call SSL_Shutdown since the TCP socket is shutdown by thread - 2 for write operation. As per my understanding this violates the TLS standard because of not sending out the close notify handshake. How to ensure to come out of blocking SSL_read and initiate SSL_shutdown from same thread? Thanks, Mahesh G S
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