On 22 Feb 2015, at 11:22 PM, Tinker <[email protected]> wrote:
> I need your authoritative answer on the following question.
[snip stuff that is too long]
You are totally overthinking this.
The SSL protocol involves negotiation, during which the sender and the receiver
exchange data with each other. What this means is that during either SSL_read,
or SSL_write, openssl might try to write or read respectively. If your
non-blocking code isn’t geared to handle this, you might end up either hanging
or spinning as you wait for the wrong event.
The SSL_WANTS_READ response code is a warning that means “I want to read during
SSL_write, are you ok with me doing this?”.
The SSL_WANTS_WRITE response code is a warning that means “I want to write
during SSL_read, are you ok with me doing this?”.
In both cases, once you have determined that it is ok to read, or ok to write,
you simply retry SSL_write() or SSL_read() again.
For example, a read loop:
sense = READ;
while (sense == READ ? if_ready_to_read() : if_ready_to_write()) {
rc = SSL_read();
if (rc == SSL_WANT_WRITE) {
sense = WRITE;
} else {
sense = READ;
}
// do stuff with what you read (you may have read nothing, but that’s fine
too)
}
Regards,
Graham
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