[stgt] tgtd and open-isns woes

[Albert Pauw]

Looking at it using wireshark I noticed the following.

Deregistering by stopping tgtd gives the following handshake sequence:

tgtd -> isnsd: SCNDereg
tgtd -> isnsd: DeregDev
isnsd -> tgtd: SCNDeregRsp
isnsd -> tgtd: DeregDevRsp

Switching isns off in tgtd gives:

tgtd -> isnsd: SCNDereg
tgtd -> isnsd: DeregDev
isnsd -> tgtd: SCNDeregRsp

After which isnsd goes into a spin.

When looking at the DeregDev command send out by tgtd I see that the 
start/stop version hands over the following payload:

iSCSI Name
Entity Identifier (aka IP address of target)

However, looking at the manual version (switching it off) I find the 
following payload, which seems to choke isnsd:

iSCSI Name
Entity Identifier (aka IP address of target)
Entity Identifier (aka IP address of target)
Entity Protocol (iSCSI)
Portal IP Address (IPv6 format)
Portal Port
SCN Port
iSCSI Name
iSCSI Node Type (target)

 From the isns rfc I find for the DeregDev command:

     The DeregDev request message payload contains a single source
     attribute (IP Address or Port Name) and key attributes (IP Address,
     DNS Name&  Path, Node Name or Port Name).


Which looks like the first (simpler) request would be the right one.
Of course isnsd shoudn't choke on it, but I think the isns code needs a 
bit of a tweak here.

Albert


On 08/06/2010 07:22 PM, Albert Pauw wrote:
> Just noticed a problem with the isns server, which comes standard with 
> Fedora and Redhat.
>
> When I start tgtd and add the isns IP number and switch it on, it 
> registers nicely.
> When I stop tgtd, it deregisters nicely.
>
> However.
>
> When I start tgtd and add the isns IP number and switch isns on, it 
> registers nicely.
> When I switch isns off in tgtd, it deregisters, but it sends isnsd 
> into a loop (96% CPU usage).
>
> Is there a difference between deregistering when shutting down, and 
> just switching it off?
>
> Cheers,
>
> Albert
>
> P.S. So the offending command sequence would be:
>
> tgtadm --op update -m sys -n iSNSServerIP -v <IP nr server>
> tgtadm --op update -m sys -n iSNS -v On
> tgtadm --op update -m sys -n iSNS -v Off

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