RE: BIO_do_connect() strange return

[Bin Lu]

>> Hi,
>> 
>> I have the following code snippet:
>> 
>> bio = BIO_new_connect(host);
>> BIO_set_conn_port(bio, port);
>> BIO_set_nbio(bio, 1)
>> while (true) {
>>     status = BIO_do_connect(bio);
>>     if (status > 0 || !BIO_should_retry(bio)) {
>>         break;
>>     }
>>    sleep(1);
>> }
>> 
>> BIO_do_connect() always returns -1 the first time and 1 the 2nd time, 
>> regardless if the server is reachable or not.
>> 
>> If I use the blocking mode, then it returns 1 on reachable server and hangs 
>> otherwise, which seems expected.
>> 
>> Is there anything wrong in the above code, why it returns the same value for 
>> reachable or non-reachable servers?
>> 
>
>A call cannot immediately determine if a server is reachable. It typically has 
>to wait until it gets >a reply from the remote server. 
>
>That's why you get a retry: the TCP stack is waiting for a response. Only when 
>it gets that response >can the connection continue or not as the case may be.

Thanks Steve. 

Why the connection is still invalid, because subsequent OCSP_sendreq_bio() 
receives no response(while in blocking mode it does), after the 2nd time call 
to BIO_do_connect() in the loop which always returns 1/success ?

It is failing in OCSP connection after the 2nd successful BIO_do_connect() call 
as soon as the BIO is made non-blocking. It works fine in blocking mode but it 
does not timeout if the server is unreachable. 

Regards,
-binlu

>Steve.
>--
>Dr Stephen N. Henson. OpenSSL project core developer.
>Commercial tech support now available see: http://www.openssl.org 
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