[smesh-users] Trouble with Smesh

Raluca Musaloiu-E. ralucam at cs.jhu.edu
Wed Jun 17 05:43:41 EDT 2009


On Tue, 16 Jun 2009, Juan - k wrote:

> I don't have much experience on Firmware and Systems installations, I 
> think I would need some help installing the Smesh System. I would really 
> thank any help since I'm really interested in doing research on this 
> system.

Glad to see you want to use SMesh. Please see my inline responses.

> - I couldn't run the smesh.wrt.setup file, but I did copy&paste each 
> line and the router configs were successfully changed (ipaddrs: 
>,,, ssid did change)

As long as you did all the settings it's fine. The setup script should 
have worked though. It's a pretty straightforward bash script. Check if the 
nvram path is set correctly. Also, while setting the IP for the wireless 
interface, make sure you set the netmask to (and not to

> - I couldn't do the 4th step (create an RSA key). I'm still working on 
> that. When I promtp "/jffs/autocopy.sh /jffs/autocopy.sh" It says 
> "dbclient: exited: string too long" after I created a pub and priv key 
> with asterisk. (how do I make .priv and .pub files with dropbear? it 
> just creates a file somewhere but no .pub or .priv).

Autocopy script fails because the the RSA key is not working properly. To 
generate dropbear keys, use dropbearkey utility (available on the router). 
The private key is generated into a file (use -f flag), while the public 
key is output on the screen:

# dropbearkey -t rsa -f db.priv
Will output 1024 bit rsa secret key to 'db.priv'
Generating key, this may take a while...
Public key portion is:
Fingerprint: md5 96:7d:ba:56:67:15:b9:4a:8b:2e:bf:a0:8f:c2:35:7a

In this case the public key is the entire line starting with 'ssh-rsa 
AAAA...'. Simply copy this line into /etc/dropbear/authorized_keys. SSH 
should work without password now.

> Computing routing time: 0
>        LOCAL NODE

Indeed, it seems that the routers don't detect each other. The way to 
create a connected network is specified by the NEIGHBORS setting from the 
/jffs/smesh.conf file. There are 2 ways to do it:

- set the neighbors manually. For instance if you want to be 
directly connected to and, set NEIGHBORS="-a -a" in's config file.

- autodiscovery mode. Each node automatically detects its neighbors. For 
this, use '-d' flag and a multicast address, like NEIGHBORS="-d".

> - I tried to connect a PC to the WMN. It connects successfully to it, 
> but it gave me the IP: (which is not a valid IP). The LAN 
> DHCP server on the router is disabled.

This is actually good. As I mentioned above, the wifi interface is in 
network, so is in the address space. The IP looks 
complicated because we generate it using a hash function applied on the 
client's hardware address. If you got that IP, our DHCP server is 
definitely running OK :).

Let us know how it goes.

Raluca ME

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