Minor feature additions

[Chris Backas <chb@xxxxxxxxxxxxxxxxxx>]

Hello all,

I'm currently upgrading from libssh 0.2 to 0.3, and in the process I'm  
looking at some minor tweaks we'd previously made for our needs to  
ensure that they'll work the same way after the upgrade. I thought  
that perhaps I should mention them here to see if they were something  
that would be generally useful to others.

Some background on how we most often use libssh. Typically we're  
dialing into (yes, with modems) remote systems all night long,  
establishing PPP, and then connecting to the remote host with SSH to  
perform some automated operations. Due to the nature of these systems,  
more often than not they have the same IP as one another over the PPP  
link (IE: They'll all be, say, 10.20.10.1) but obviously have  
different signatures. It is also typically the case that we don't have  
DNS facilities for this. Anyway, our tweaks:

1) The known hosts file: Current libssh considers it an error  
condition if this does not exist. I don't really see why, but it  
causes us problems on our production machines because typically no  
one's ever run ssh on them directly before, so the file isn't there to  
begin with. We see no reason to have to go around to every machine and  
ensure this file exists first, so I did a simple modification in the  
0.2 release that changes "file not found"  in ssh_parse_knownhost()  
from an error condition to a simple "return NULL", meaning "No match  
found".

Could there be a simple option which determines whether not having a  
known hosts file is a real problem?

2) In getai(), it saves a lot of futile DNS querying time to do  
something like this:
hints.ai_flags |= AI_NUMERICHOST;

Obviously, if you know ahead of time that you're supplying a plain IP  
Address. Could there be a way to tell libssh that this is the case and  
add that flag to the hints conditionally?

Thoughts?

Chris Backas
Software Developer
Bristol Capital, Inc.