Re: Blocking on a non-blocking socket?
Wiebe Cazemier via openssl-users <[email protected]>
| Newsgroups | gmane.comp.encryption.openssl.user |
|---|---|
| Message-ID | <[email protected]> |
Hi Detlef, ----- Original Message ----- > From: "Detlef Vollmann" <[email protected]> > To: [email protected] > Sent: Friday, 24 May, 2024 12:02:37 > Subject: Re: Blocking on a non-blocking socket? > > That's correct, but if I understand Matt correctly, this isn't the case. > The idea of SSL_MODE_AUTO_RETRY is that if there's data, but it isn't > application data but some kind of handshake data, then SSL_read doesn't > return (after handling the handshake data), but immediately retries. > If this retry fails with EWOULDBLOCK (or actually BIO_read returns 0), > then SSL_read returns with 0 and SSL_WANT_READ. Wouldn't the option then have to be called 'read more than one record at a time'? To me, 'retry' is a bit of a misnomer in that description. Tracing the code, the retry seems to be considered based on BIO_fd_non_fatal_error(), which looks at EWOULDBLOCK. See [1] and [2]. Wiebe [1] https://github.com/openssl/openssl/blob/b9e084f139c53ce133e66aba2f523c680141c0e6/crypto/bio/bss_fd.c#L226 [2] https://github.com/openssl/openssl/blob/b9e084f139c53ce133e66aba2f523c680141c0e6/crypto/bio/bss_fd.c#L113