Re: Need Help Regarding::SSH blocking and Non-Blocking Mode

[Jakub Jelen <jjelen@xxxxxxxxxx>]

On 4/5/21 12:28 PM, V Sidnal, Nagraju wrote:
> Hi All,
>
> When I’m creating a session, by default it create blocking session.
>
> If I use same blocking session to call *SSH_CONNECT(SESSION),* with 
> timeout of 30 Seconds, For Invalid IP address it gets return after 30 
> seconds.
>
> When I set this to nonblocking by using *ssh_set_blocking(SESSION,0)**, 
> If now, I do SSH_CONNECT(SESSION),* it returns immediately with*SSH_AGAIN.*
>
> It means in nonblocking mode I need to try *SSH_CONNECT(SESSION) 
> *repeatedly, until my expected timeout value  or return SSH_OK, example 
> in my case for 30 seconds.
>
> Apart from above observation, What is the impact of  blocking and 
> non-blocking mode?
>
> Which one is recommended. Which one to use in which scenarios.

It only shifts the responsibilities between your application and the 
library. If you do not want to bother with timeouts, using blocking mode 
is better for your application. If you have work to be done in the 
meantime or you use some custom polling, non-blocking operations (not 
just connect) are more suitable for your application.

Regards,
--
Jakub Jelen
Senior Software Engineer
Crypto Team, Security Engineering
Red Hat, Inc.