SSL: workaround for incorrect SSL_write() errors in OpenSSL 1.1.1. OpenSSL 1.1.1 fails to return SSL_ERROR_SYSCALL if an error happens during SSL_write() after close_notify alert from the peer, and returns SSL_ERROR_ZERO_RETURN instead. Broken by this commit, which removes the "i == 0" check around the SSL_RECEIVED_SHUTDOWN one: https://git.openssl.org/?p=openssl.git;a=commitdiff;h=8051ab2 In particular, if a client closed the connection without reading the response but with properly sent close_notify alert, this resulted in unexpected "SSL_write() failed while ..." critical log message instead of correct "SSL_write() failed (32: Broken pipe)" at the info level. Since SSL_ERROR_ZERO_RETURN cannot be legitimately returned after SSL_write(), the fix is to convert all SSL_ERROR_ZERO_RETURN errors after SSL_write() to SSL_ERROR_SYSCALL.