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omshell lease ends field invalid characters

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Rick Dicaire

omshell lease ends field invalid characters

Hi folks, I wrote a script that invokes omshell and noticed a couple leases having non hex values in the 'ends' field. Checking those leases in /var/state/dhcp/dhcpd.leases shows valid dates.

Running dhcpd 4.4.2 with a customized ddns configuration.

From dhcpd.leases:

lease 192.168.17.158 {
starts 2 2020/09/29 06:17:17;
ends 2 2020/09/29 18:17:17;
cltt 2 2020/09/29 06:43:07;
binding state active;
next binding state free;
rewind binding state free;
hardware ethernet f4:f5:d8:42:52:10;
set ddns-rev-name = "158.17.168.192.in-addr.arpa.";
set ddns-txt = "004a9b9d459dc48a4aae47026174068ad9";
set ddns-fwd-name = "Chromecast.dhcp.labdev.";
set clientddns = "Chromecast";
set clienthost = "Chromecast";
set clientmac = "f4:f5:d8:42:52:10";
set clientip = "192.168.17.158";
set clientdomain = "dhcp.labdev.";
set vendor-class-identifier = "dhcpcd-6.8.2:Linux-3.8.13+:armv7l:Marvell";
client-hostname "Chromecast";
on expiry {
execute ("/usr/local/sbin/hook_dhcpd.sh", "expiry", clientip,
concat (concat (clientddns, "."), clientdomain), clienthost, clientmac);
}
on release {
execute ("/usr/local/sbin/hook_dhcpd.sh", "release", clientip,
concat (concat (clientddns, "."), clientdomain), clienthost, clientmac);
}
}

From omshell output:

echo "server dns1
key daw3-ddns keyval
connect
new lease
set ip-address = 192.168.17.158
open"|omshell
> > > obj: <null>
> obj: lease
> obj: lease
ip-address = c0:a8:11:9e
> obj: lease
ip-address = c0:a8:11:9e
state = 00:00:00:02
client-hostname = "Chromecast"
subnet = 00:00:00:03
pool = 00:00:00:04
hardware-address = f4:f5:d8:42:52:10
hardware-type = 00:00:00:01
ends = "_sz-"
starts = 5f:72:d1:6d
tstp = 00:00:00:00
tsfp = 00:00:00:00
atsfp = 00:00:00:00
cltt = 5f:72:d7:7b
flags = 00
ddns-rev-name = "158.17.168.192.in-addr.arpa."
ddns-txt = "004a9b9d459dc48a4aae47026174068ad9"
ddns-fwd-name = "Chromecast.dhcp.labdev."
clientddns = "Chromecast"
clienthost = "Chromecast"
clientmac = "f4:f5:d8:42:52:10"
clientip = "192.168.17.158"
clientdomain = "dhcp.labdev."
vendor-class-identifier = "dhcpcd-6.8.2:Linux-3.8.13+:armv7l:Marvell"

As shown above, 'ends' field does not have a hex value.

Any thoughts as to what's causing this?

Thanks

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Rick Dicaire

Re: omshell lease ends field invalid characters

Wow great catch...the date value of your hex conversion corresponds with what I see in dhcpd.leases.
I can try and script for this, but should a bug be filed, or could this be a terminal issue (I get same result from console terminal and xterm/ssh session)?

On Tue, Sep 29, 2020 at 12:09 PM Rick Dicaire <[hidden email]> wrote:

Wow great catch...the date value of your hex conversion corresponds with what I see in dhcpd.leases.
I can try and script for this, but should a bug be filed, or could this be a terminal issue (I get same result from console terminal and xterm/ssh session)?

On Tue, Sep 29, 2020 at 8:32 AM Bruce Hudson <[hidden email]> wrote:
> ends = "_sz-"
> starts = 5f:72:d1:6d

> As shown above, 'ends' field does not have a hex value.
> Any thoughts as to what's causing this?

I suspect this is just an anomaly cause by omshell's more
generic output algorithm. Because all four bytes of the ends
value correspond to printable characters, it displays it as
a string instead of the raw octects. A (failed in this case)
effort to be more user friendly.

Looking at the ord's of the four characters in hex:

"_sz-" ==> 5f:73:7a:2d
--
Bruce A. Hudson | [hidden email]
ITS, Networks and Systems |
Dalhousie University |
Halifax, Nova Scotia, Canada | (902) 494-3405