[Click] Terminating connections to click running in kernel mode

[Eddie Kohler]

Hi George,

> When I 
> run the same configuation in kernel mode (after changing "Discard" to 
> "ToHost"), click still forwards packets fine, but I can no longer telnet, 
> ssh, or otherwise connect to the machine.  If I try to telnet to the machine 
> itself, I get the SYN, SYNACK, and ACK, but nothing else.  Connections that 
> are already open (open and idle telnets, for example), continue to work fine.
> 
> Has anyone else experienced this problem?  It's becoming a problem because the 
> machines that I'm running click on are actually diskless machines, and so the 
> inability to make new connections means they crash when an NFS request of any 
> kind is made :-)
> 
> I've instrumented the click code and the packets are in fact getting to the 
> "ToHost" element (but they don't seem to be getting form that element to 
> Linux itself).  I generated the click configuration file with the 
> "make-ip-conf.pl" script (changing Discard to ToHost when running in kernel 
> mode).  The machine is running Redhat 9 (2.4.20) and there are three 3com 
> 3c905-c-tx-m cards (using the 3c90x driver).  Everything works fine in 
> usermode.

So you actually get a SYNACK out from the machine, but nothing else??  I
don't remember seeing that before.

Have you provided ToHost with a device pointer?  Did you see any messages
in dmesg that look like "%{element}: dropped a packet with null skb->dev"?

Please send along your configuration also.

Eddie