[Kea-users] Set domain-search option for dhcp4

[Olivier Clavel]

My ascii table got scrambled with mail fixed column width. Here is the same
in a gist:
https://gist.github.com/zeitounator/0efdd5b24eaf84d953248c651fc37dba

On Tue, 21 Feb 2017 at 10:12 Olivier Clavel <olivier.clavel at gmail.com>
wrote:

> Just tested a slightly more complicated example using data compression for
> 2 sub domains:
>
> => example.com ip4.example.com
>
> 1 - convert string to hex
>
> e  x  a  m  p  l  e  .  c  o  m    i  p  4  .  e  x  a  m  p  l  e  .  c
>  o  m
> 65 78 61 6d 70 6c 65 2e 63 6f 6d   69 70 34 2e 65 78 61 6d 70 6c 65 2e 63
> 6f 6d
>
> 2 - remove redundancy
>
> e  x  a  m  p  l  e  .  c  o  m    i  p  4
> 65 78 61 6d 70 6c 65 2e 63 6f 6d   69 70 34
>
> 3- drop the dots, preprend each element with number of chars, terminate
> first record with null
>
> 7) e  x  a  m  p  l  e  3)  c  o  m  null 3)  i  p  4
> 07 65 78 61 6d 70 6c 65 03  63 6f 6d 00   03  69 70 34
>
> 4- terminate second record (and next ones if any...) with a 2 byte pointer
> to record ending offset in chain
>
>
> +------+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
> |offset| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 |11 |12 |13 |14 |15 |16 |17 |18 |
> +------+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
>
> |data  | 7 |'e'|'x'|'a'|'m'|'p'|'l'|'e'| 3 |'c'|'o'|'m'|   | 3 |'i'|'p'|'4'|xC0|x00|
> +------+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
>
> |hex   | 07| 65| 78| 61| 6d| 70| 6c| 65| 03| 63| 6f| 6d| 00| 03| 69| 70| 34| C0| 00|
> +------+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
>
>        |           element 1           |  element 2    |   |  element 3    | ^   ^
>
>        |                       domain 1                    |        domain 2 !   ! |
>
>                                            Pointer
> indicator-----------------!   !
>                                                     Offset of
> element------------!
> 3- copy result to config file
> "option-data" : [{
>     "name": "domain-search",
>     "data": "076578616d706c6503636f6d0003697034C000",
>     "csv-format": false
> }]
>
>
> On Tue, 21 Feb 2017 at 08:09 Olivier Clavel <olivier.clavel at gmail.com>
> wrote:
>
> In case someone comes other this thread with the same problem...
>
> After reading the RFC (https://tools.ietf.org/search/rfc3397) and
> struggling a bit, here is how to work around the problem until the future
> enhancement is developed (see ticket below). Please read the rfc if you
> need more than one domain. Example below for a single one.
>
> 1 - convert string to hex (conversion tool here:
> http://www.swingnote.com/tools/texttohex.php)
>
> e  x  a  m  p  l  e  .  c  o  m
> 65 78 61 6d 70 6c 65 2e 63 6f 6d
>
> 2 - drop the dots, prepend each element with number of chars and finish
> with null
> 7) e  x  a  m  p  l  e  3) c  o  m  (null)
> 07 65 78 61 6d 70 6c 65 03 63 6f 6d 00
>
> 3- copy result to config file
> "option-data" : [{
>     "name": "domain-search",
>     "data": "076578616d706c6503636f6d00",
>     "csv-format": false
> }]
>
>
> On Mon, 20 Feb 2017 at 18:42 James Sumners <JamesSumners at clayton.edu>
> wrote:
>
> I can tell you that it *does* have to be in encoded binary format —
> http://kea.isc.org/ticket/5087
>
>
>
>
> On February 20, 2017 at 12:32:33 PM, Olivier Clavel (
> olivier.clavel at gmail.com) wrote:
>
> Hello everyone.
>
> Sorry to come here with a question that seems so basic. Unfortunately, I
> can't find the way to set the domain-search option correctly sent back to
> the dhcp4 client. This is what I've tried so far with the result.
>
> 1)
> "option-data": [ {"name": "domain-search", "data": "clavel.loc"} ]
>
> Kea refuses to start with following errors.
>
> 2017-02-18 15:25:53.899 ERROR [kea-dhcp4.dhcp4/3379] DHCP4_PARSER_FAIL
> failed to create or run parser for configuration element subnet4: option
> data does not match option definition (space: dhcp4, code: 119): unable to
> cast clavel.loc to binary data type: attempt to decode a value not in
> base16 char set (/etc/kea/kea-dhcp4.conf:337:51)
> 2017-02-18 15:25:53.899 ERROR [kea-dhcp4.dhcp4/3379]
> DHCP4_CONFIG_LOAD_FAIL configuration error using file:
> /etc/kea/kea-dhcp4.conf, reason: option data does not match option
> definition (space: dhcp4, code: 119): unable to cast clavel.loc to binary
> data type: attempt to decode a value not in base16 char set
> (/etc/kea/kea-dhcp4.conf:337:51)
> 2017-02-18 15:25:53.900 ERROR [kea-dhcp4.dhcp4/3379] DHCP4_INIT_FAIL
> failed to initialize Kea server: configuration error using file
> '/etc/kea/kea-dhcp4.conf': option data does not match option definition
> (space: dhcp4, code: 119): unable to cast clavel.loc to binary data type:
> attempt to decode a value not in base16 char set
> (/etc/kea/kea-dhcp4.conf:337:51)
>
>
> 2)
> "option-data": [ {"name": "domain-search", "data": "636C6176656C2E6C6F63"}
> ]
> "option-data": [ {"name": "domain-search", "data":
> "636C6176656C2E6C6F63"}, "csv-format": false ]
>
> In both cases, the server starts correctly but then the following error
> appears in dhcp client:
>
> Invalid domain list.
> suspect value in domain_search option - discarded
>
>
> Is there some part of the doc I missed ? Thanks in advance for your
> answers.
>
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