[Kea-users] Kea 1.2.0 - not finding host reservation via flex-id & pgsql

[Jason Lixfeld]

> On Sep 15, 2017, at 3:57 PM, Thomas Markwalder <tmark at isc.org> wrote:
> 
> On 9/15/17 2:12 PM, Jason Lixfeld wrote:
>> 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 at 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 at 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
>> Kea-users at lists.isc.org
>> https://lists.isc.org/mailman/listinfo/kea-users
> Hello Jason:
> 
> We're looking into this for you.  In the meantime you could try
> prepending '\x' onto the identifier value you inserted.

Hi Thomas,

I did attempt this initially, but it wasn’t successful:

…
\set identifier_value '\x010972677730312e6c616200040c370201'
...

kea=# select dhcp_identifier from hosts;
                           dhcp_identifier
----------------------------------------------------------------------
 \x013039373236373737333033313265366336313632303030343063333730323031
(1 row)

kea=# select convert_from('\x013039373236373737333033313265366336313632303030343063333730323031', 'UTF-8');
             convert_from
--------------------------------------
 \x010972677730312e6c616200040c370201
(1 row)

kea=#

kea=# 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;
kea=#

 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)


> Regards,
> 
> Thomas Markwalder
> ISC Software Engineering
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