87 lines
4.8 KiB
Markdown
87 lines
4.8 KiB
Markdown
|
# DHCPv6 prefix delegation {#dhcp6_pd_doc}
|
||
|
|
|
||
|
|
DHCPv6 prefix delegation client implementation is split between Control Plane and Data Plane.
|
||
|
|
Data Plane can also be used alone by external application (external Control Plane) using Data Plane Binary API.
|
||
|
|
|
||
|
|
Number of different IA\_PDs managed by VPP is currently limited to 1 (and corresponding IAID has value 1).
|
||
|
|
Client ID is of type DUID-LLT (Link Layer address plus time) and is created on VPP startup from avaliable interfaces (or chosen at random for debugging purposes).
|
||
|
|
Server ID is only visible to Data Plane. Control Plane identifies servers by a 32-bit handle (server\_index) mapped to Server ID by Data Plane.
|
||
|
|
|
||
|
|
## Control Plane
|
||
|
|
|
||
|
|
DHCPv6 PD clients are configured per interface.
|
||
|
|
When configuring a PD client we have to choose a name of a prefix group for that client.
|
||
|
|
Each prefix obtained through this client will be flagged as belonging to specified prefix group.
|
||
|
|
The prefix groups are used as a filter by prefix consumers.
|
||
|
|
|
||
|
|
To enable client on particular interface call Binary API function dhcp6\_pd\_client\_enable\_disable with param 'sw\_if\_index' set to that interface,
|
||
|
|
'prefix\_group' set to prefix group name and 'enable' set to true.
|
||
|
|
Format of corresponding Debug CLI command is: "dhcp6 pd client <interface> [disable]"
|
||
|
|
|
||
|
|
To add/delete IPv6 address potentially using available prefix from specified prefix group call Binary API command ip6\_add\_del\_address\_using\_prefix with parameters:
|
||
|
|
> sw\_if\_index - software interface index of interface to add/delete address to/from
|
||
|
|
> prefix\_group - name of prefix group, prefix\_group[0] == '\0' means no prefix should be used
|
||
|
|
> address - address or suffix to be used with a prefix from selected group
|
||
|
|
> prefix\_length - subnet prefix for the address
|
||
|
|
> is\_add - 1 for add, 0 for remove
|
||
|
|
or Debug CLI command with format: "set ip6 addresses <interface> [prefix group <n>] <address> [del]"
|
||
|
|
|
||
|
|
When no prefix is avaliable, no address is physically added, but is added once a prefix becomes avaliable.
|
||
|
|
Address is removed when all available prefixes are removed.
|
||
|
|
When a used prefix is removed and there is other available prefix, the address that used the prefix is reconfigured using the available prefix.
|
||
|
|
|
||
|
|
There are three debug CLI commands (with no parameters) used to show the state of clients, prefixes and addresses:
|
||
|
|
show ip6 pd clients
|
||
|
|
show ip6 prefixes
|
||
|
|
show ip6 addresses
|
||
|
|
|
||
|
|
### Example configuration
|
||
|
|
|
||
|
|
set int state GigabitEthernet0/8/0 up
|
||
|
|
dhcp6 pd client GigabitEthernet0/8/0 prefix group my-dhcp6-pd-group
|
||
|
|
set ip6 address GigabitEthernet0/8/0 prefix group my-dhcp6-pd-group ::7/64
|
||
|
|
|
||
|
|
## Data Plane
|
||
|
|
|
||
|
|
First API message to be called is dhcp6\_clients\_enable\_disable with enable parameter set to 1.
|
||
|
|
It enables DHCPv6 client subsystem to receive UDP messages containing DHCPv6 client port (sets the router to DHCPv6 client mode).
|
||
|
|
This is to ensure client subsystem gets the messages instead of DHCPv6 proxy subsystem.
|
||
|
|
|
||
|
|
There is one common Binary API call for sending DHCPv6 client messages (dhcp6\_pd\_send\_client\_message) with these fields:
|
||
|
|
> msg\_type - message type (e.g. Solicit)
|
||
|
|
> sw\_if\_index - index of TX interface
|
||
|
|
> server\_index - used to dentify DHCPv6 server,
|
||
|
|
unique for each DHCPv6 server on the link,
|
||
|
|
value obrtained from dhcp6\_pd\_reply\_event API message,
|
||
|
|
use ~0 to send message to all DHCPv6 servers
|
||
|
|
> param irt - initial retransmission time
|
||
|
|
> param mrt - maximum retransmission time
|
||
|
|
> param mrc - maximum retransmission count
|
||
|
|
> param mrd - maximum retransmission duration for sending the message
|
||
|
|
> stop - if non-zero then stop resending the message, otherwise start sending the message
|
||
|
|
> T1 - value of T1 in IA\_PD option
|
||
|
|
> T2 - value of T2 in IA\_PD option
|
||
|
|
> prefixes - list of prefixes in IA\_PD option
|
||
|
|
|
||
|
|
The message is automatically resent by Data Plane based on parameters 'irt', 'mrt', 'mrc' and 'mrd'.
|
||
|
|
To stop the resending call the same function (same msg\_type is sufficient) with 'stop' set to 1.
|
||
|
|
|
||
|
|
To subscribe for notifications of DHCPv6 messages from server call Binary API function
|
||
|
|
want\_dhcp6\_pd\_reply\_events with enable\_disable set to 1
|
||
|
|
Notification (dhcp6\_pd\_reply\_event) fileds are:
|
||
|
|
> sw\_if\_index - index of RX interface
|
||
|
|
> server\_index - used to dentify DHCPv6 server, unique for each DHCPv6 server on the link
|
||
|
|
> msg\_type - message type
|
||
|
|
> T1 - value of T1 in IA\_PD option
|
||
|
|
> T2 - value of T2 in IA\_PD option
|
||
|
|
> inner\_status\_code - value of status code inside IA\_PD option
|
||
|
|
> status\_code - value of status code
|
||
|
|
> preference - value of preference option in reply message
|
||
|
|
> prefixes - list of prefixes in IA\_PD option
|
||
|
|
|
||
|
|
Prefix is a struct with with these fields:
|
||
|
|
> prefix - prefix bytes
|
||
|
|
> prefix\_length - prefix length
|
||
|
|
> valid\_time - valid lifetime
|
||
|
|
> preferred\_time - preferred lifetime
|