Hi,
I have an application that does its network I/O using OpenSSL to make
the code more portable, but which only optionally uses encryption. Now,
I want my read/write calls to be nonblocking, i.e., to always return
right away. I need to do this on Unix, which is what I'm familiar with,
and on Windows, to which I'm new although I managed to build my client
app using MinGW.
Here's a sketch (error handling snipped) of my OpenSSL code:
/* If we use encryption, we have an SSL_CTX in ctx */
if (ctx) {
bio = BIO_new_ssl_connect(ctx);
BIO_set_conn_hostname(bio, hostname);
BIO_do_connect(bio);
BIO_do_handshake(bio);
} else { /* no encryption case */
bio = BIO_new_connect(hostname);
BIO_do_connect(bio);
}
Later I use BIO_read() and BIO_write() for the I/O. My questions now
are:
- Am I correct in assuming that SSL_read()/SSL_write() imply the use of
encryption -- I can find more code examples using those but I want a
transparent API regardless of whether encryption is used or not.
- With a chain created using BIO_new_ssl_connect(), which fd is the
critical one to set nonblocking (I presume it's just the one of the bio
returned by BIO_new_ssl_connect() -- that's what I'm doing on Unix and
it works).
- On Windows, I've tried multiple ways of obtaining the socket/file
descriptor of the bios involved, and then setting that nonblocking using
ioctlsocket(), but no matter which bio I pick and how I call
BIO_get_fd() I get an error that WSAGetLastError() says means "not a
socket". Can someone please show me how to do this on Windows because I
don't get it.
- More precisely, if it's the file descriptor of the bio returned by
BIO_new_ssl_connect() that I need to set nonblocking, how do I do that
on Windows because that's an SSL BIO and thus doesn't use a socket
underneath (right?) -- I don't even find a Windows API function to use
for that.
I've seen
http://www.mail-archive.com/[EMAIL PROTECTED]/msg00540.html
which was helpful but didn't solve it.
As usual, sorry if this has been answered before -- I've done my
googling and cannot find an answer for the entire context. Viega,
Messier and Chandra say "these omitted functions can be implemented
easily" on page 164, which reminds me of the way I shortcut my math
proofs in Uni as "obvious" when I had no idea how to do them ;)
Thanks a lot in advance!
Christian.
ps: no need to cc me, I'm subscribed.
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