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List:       kde-core-devel
Subject:    move lisa (LAN Information Server) from kdenonbeta to kdenetwork ?
From:       aleXXX <alexander.neundorf () rz ! tu-ilmenau ! de>
Date:       2000-12-14 22:31:50
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Hi,

in kdenonbeta there are kio_lan and kio_rlan, they contain lisa, reslisa, the 
ioslaves and the kcm modules.

lisa is the Lan Information Server.
It has to run with root privileges to open a raw socket, this socket is 
created immediatly after program start and then the privileges are dropped 
immediatly and never regained.

Well, what does it ?
You give it a number or range of IP-addresses you are interested in (e.g. a 
part of you local network) and then lisa sends periodically ICMP echo 
requests to these IP addresses. You can also say lisa to do a broadcast 
nmblookup, so that you get the names of all smb-servers in your subnet, this 
should create less network traffic.

The collected hosts are presented on TCP port  7741.
You can restrict the hosts which are allowed to access the port via a 
address/mask or single addresses. The address mask does not have to be your 
own netaddress/netmask, you can make it as strict as you want to.

To reduce the network load this produces I implemented two things:

all lisa servers in  LAN cooperate: before a server starts pinging, it sends 
a broadcast which asks if there is another server which already does this.
If lisa receives an answer, it connects to port 7741 of the one who answered 
and retrieves the list fromn this server. This way always only *one* server 
should send pings. If this server shuts down, nobody will answer the next 
boradcast and the sender of the broadcast will become the next machine who 
does the work (successfully tested with two running lisa's)

second, if nobody accesses the data from the TCP port for one period between 
updating (e.g. 10 minutes), the update period is doubled. This way the update 
period can become 16times the initial timeout.
It is set to to the initial value if somebody accesses the port.

This is basically what lisa does.
There is also resLisa, the restricted version.
With this you are not able to ping whole ranges of addresses, but only single 
addresses and you can do the nmblookup-thingie.
reslisa servers also *don't* cooperate and present the information only via a 
UNIX-domain socket, not a real network socket.
This way it should not create a potential security risk.

lisa is intended to be run by root on boot time, reslisa is intended to 
setuid root and to be run by every user who wants to.

This way you can simply type lan:/ and you get a list of all hosts in your 
network. If you know a machine which has lisa running, you can of course 
always contact this server lan://some_host/, then you don't have to run lisa.

The hosts are presented as dirs, if you open one host, the lan/rlan ioslaves 
check the ftp, nfs, http, smb ports of this host. You can configure which of 
them should be checked and which not.

I think it is already quite stable and bug free, it won't get better without 
users.

So I'd like if it was moved to kdenetwork.
I'm not sure whether it has some big/little endian issues and 64bit issues.

So what do you think ?

Bye
Alex


["lan1.png" (image/png)]

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