Hello,
I was troubleshooting an issue with host reservations via flex-id and
postgresql.
I tracked it down to a difference in how the database was storing
identifier_value, vs. how the identifier_expression is configured in the kea
config file.
The kea debug shows the generated flex-id:
2017-09-15 13:32:01.182 DEBUG [kea-dhcp4.packets/631] DHCP4_FLEX_ID flexible
identifier generated for incoming packet:
flex-id=010972677730312E6C616200040C370201
The kea config identifier_expression is like so:
"hooks-libraries": [
{
"library": "/usr/local/lib/hooks/libdhcp_flex_id.so",
"parameters":
{
"identifier-expression":
"concat(relay4[2].hex,relay4[1].hex)"
}
}
],
I set the identifier_value per the how-to
(https://kea.isc.org/wiki/HostReservationsHowTo) to match what the kea debug
generated for the flex-id:
…
…
kea=# \set identifier_value ‘010972677730312e6c616200040c370201'
…
…
When I noticed that the reservation was not working, I looked at the postgres
query that Kea was making, and it appears as though $3 is prepended with \x :
2017-09-15 13:32:01.189 EDT [726] kea@kea LOG: execute get_host_subid4_dhcpid:
SELECT h.host_id, h.dhcp_identifier, h.dhcp_identifier_type,
h.dhcp4_subnet_id, h.dhcp6_subnet_id, h.ipv4_address, h.hostname,
h.dhcp4_client_classes, h.dhcp6_client_classes, h.dhcp4_next_server,
h.dhcp4_server_hostname, h.dhcp4_boot_file_name, o.option_id, o.code,
o.value, o.formatted_value, o.space, o.persistent FROM hosts AS h LEFT JOIN
dhcp4_options AS o ON h.host_id = o.host_id WHERE h.dhcp4_subnet_id = $1 AND
h.dhcp_identifier_type = $2 AND h.dhcp_identifier = $3 ORDER BY h.host_id,
o.option_id
2017-09-15 13:32:01.189 EDT [726] kea@kea DETAIL: parameters: $1 = '1', $2 =
'4', $3 = '\x010972677730312e6c616200040c370201’
Making that query directly of course fails, which is where the issue lies:
SELECT h.host_id, h.dhcp_identifier, h.dhcp_identifier_type,
h.dhcp4_subnet_id, h.dhcp6_subnet_id, h.ipv4_address, h.hostname,
h.dhcp4_client_classes, h.dhcp6_client_classes, h.dhcp4_next_server,
h.dhcp4_server_hostname, h.dhcp4_boot_file_name, o.option_id, o.code,
o.value, o.formatted_value, o.space, o.persistent FROM hosts AS h LEFT JOIN
dhcp4_options AS o ON h.host_id = o.host_id WHERE h.dhcp4_subnet_id = '1' AND
h.dhcp_identifier_type = '4' AND h.dhcp_identifier =
'\x010972677730312e6c616200040c370201' ORDER BY h.host_id, o.option_id;
host_id | dhcp_identifier | dhcp_identifier_type | dhcp4_subnet_id |
dhcp6_subnet_id | ipv4_address | hostname | dhcp4_client_classes |
dhcp6_client_classes | dhcp4_next_server | dhcp4_server_hostname |
dhcp4_boot_file_name | option_id | code | value | formatted_value | space |
persistent
---------+-----------------+----------------------+-----------------+-----------------+--------------+----------+----------------------+----------------------+-------------------+-----------------------+----------------------+-----------+------+-------+-----------------+-------+------------
(0 rows)
If I remove the leading \x from the query, the expected results are presented:
SELECT h.host_id, h.dhcp_identifier, h.dhcp_identifier_type,
h.dhcp4_subnet_id, h.dhcp6_subnet_id, h.ipv4_address, h.hostname,
h.dhcp4_client_classes, h.dhcp6_client_classes, h.dhcp4_next_server,
h.dhcp4_server_hostname, h.dhcp4_boot_file_name, o.option_id, o.code,
o.value, o.formatted_value, o.space, o.persistent FROM hosts AS h LEFT JOIN
dhcp4_options AS o ON h.host_id = o.host_id WHERE h.dhcp4_subnet_id = '1' AND
h.dhcp_identifier_type = '4' AND h.dhcp_identifier =
'010972677730312e6c616200040c370201' ORDER BY h.host_id, o.option_id;
host_id | dhcp_identifier
| dhcp_identifier_type | dhcp4_subnet_id | dhcp6_subnet_id | ipv4_address |
hostname | dhcp4_client_classes | dhcp6_client_classes | dhcp4_next_server |
dhcp4_server_hostname | dhcp4_boot_file_name | option_id | code | value |
formatted_value | space | persistent
---------+------------------------------------------------------------------------+----------------------+-----------------+-----------------+--------------+----------+----------------------+----------------------+-------------------+-----------------------+----------------------+-----------+------+-------+-----------------+-------+------------
6 |
\x30313039373236373737333033313265366336313632303030343063333730323031 |
4 | 1 | | 171966277 | |
| | |
| bootfile.efi | | | | |
|
(1 row)
Manually decoding the dhcp_identifier shows the non-prepended value:
kea=# select
convert_from('\x30313039373236373737333033313265366336313632303030343063333730323031',
'UTF-8');
convert_from
------------------------------------
010972677730312e6c616200040c370201
(1 row)
kea=#
So my question is did I misinterpret the instructions (either by cluelessness
or oversight) when setting this up, or is this a bug?
Thanks!
_______________________________________________
Kea-users mailing list
[email protected]
https://lists.isc.org/mailman/listinfo/kea-users
