f47122e07e
Type: improvement Change-Id: I7e821cce1feae229e1be4baeed249b9cca658135 Signed-off-by: Nathan Skrzypczak <nathan.skrzypczak@gmail.com>
114 lines
4.8 KiB
ReStructuredText
114 lines
4.8 KiB
ReStructuredText
DHCPv6 prefix delegation
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========================
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| DHCPv6 prefix delegation client implementation is split between
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Control Plane and Data Plane.
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| Data Plane can also be used alone by external application (external
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Control Plane) using Data Plane Binary API.
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| Number of different IA_PDs managed by VPP is currently limited to 1
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(and corresponding IAID has value 1).
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| Client ID is of type DUID-LLT (Link Layer address plus time) and is
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created on VPP startup from avaliable interfaces (or chosen at random
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for debugging purposes).
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| Server ID is only visible to Data Plane. Control Plane identifies
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servers by a 32-bit handle (server_index) mapped to Server ID by Data
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Plane.
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Control Plane
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-------------
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| DHCPv6 PD clients are configured per interface.
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| When configuring a PD client we have to choose a name of a prefix
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group for that client.
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| Each prefix obtained through this client will be flagged as belonging
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to specified prefix group.
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| The prefix groups are used as a filter by prefix consumers.
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| To enable client on particular interface call Binary API function
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dhcp6_pd_client_enable_disable with param ‘sw_if_index’ set to that
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interface, ‘prefix_group’ set to prefix group name and ‘enable’ set to
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true.
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| Format of corresponding Debug CLI command is: “dhcp6 pd client
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[disable]”
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To add/delete IPv6 address potentially using available prefix from
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specified prefix group call Binary API command
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ip6_add_del_address_using_prefix with parameters:
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> sw_if_index - software interface index of interface to add/delete
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address to/from > prefix_group - name of prefix group, prefix_group[0]
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== ‘\\0’ means no prefix should be used > address - address or suffix to
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be used with a prefix from selected group > prefix_length - subnet
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prefix for the address > is_add - 1 for add, 0 for remove or Debug CLI
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command with format: “set ip6 addresses [prefix group ]
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.. raw:: html
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<address>
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[del]”
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| When no prefix is avaliable, no address is physically added, but is
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added once a prefix becomes avaliable.
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| Address is removed when all available prefixes are removed.
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| When a used prefix is removed and there is other available prefix, the
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address that used the prefix is reconfigured using the available
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prefix.
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| There are three debug CLI commands (with no parameters) used to show
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the state of clients, prefixes and addresses:
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| show ip6 pd clients
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| show ip6 prefixes
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| show ip6 addresses
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Example configuration
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~~~~~~~~~~~~~~~~~~~~~
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set int state GigabitEthernet0/8/0 up dhcp6 pd client
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GigabitEthernet0/8/0 prefix group my-dhcp6-pd-group set ip6 address
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GigabitEthernet0/8/0 prefix group my-dhcp6-pd-group ::7/64
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Data Plane
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----------
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| First API message to be called is dhcp6_clients_enable_disable with
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enable parameter set to 1.
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| It enables DHCPv6 client subsystem to receive UDP messages containing
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DHCPv6 client port (sets the router to DHCPv6 client mode).
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| This is to ensure client subsystem gets the messages instead of DHCPv6
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proxy subsystem.
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| There is one common Binary API call for sending DHCPv6 client messages
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(dhcp6_pd_send_client_message) with these fields:
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| > msg_type - message type (e.g. Solicit) > sw_if_index - index of TX
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interface > server_index - used to dentify DHCPv6 server, unique for
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each DHCPv6 server on the link, value obrtained from
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dhcp6_pd_reply_event API message, use ~0 to send message to all DHCPv6
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servers > param irt - initial retransmission time > param mrt -
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maximum retransmission time > param mrc - maximum retransmission count
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> param mrd - maximum retransmission duration for sending the message
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> stop - if non-zero then stop resending the message, otherwise start
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sending the message > T1 - value of T1 in IA_PD option > T2 - value of
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T2 in IA_PD option > prefixes - list of prefixes in IA_PD option
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| The message is automatically resent by Data Plane based on parameters
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‘irt’, ‘mrt’, ‘mrc’ and ‘mrd’.
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| To stop the resending call the same function (same msg_type is
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sufficient) with ‘stop’ set to 1.
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| To subscribe for notifications of DHCPv6 messages from server call
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Binary API function
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| want_dhcp6_pd_reply_events with enable_disable set to 1
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| Notification (dhcp6_pd_reply_event) fileds are:
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| > sw_if_index - index of RX interface > server_index - used to dentify
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DHCPv6 server, unique for each DHCPv6 server on the link > msg_type -
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message type > T1 - value of T1 in IA_PD option > T2 - value of T2 in
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IA_PD option > inner_status_code - value of status code inside IA_PD
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option > status_code - value of status code > preference - value of
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preference option in reply message > prefixes - list of prefixes in
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IA_PD option
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| Prefix is a struct with with these fields:
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| > prefix - prefix bytes > prefix_length - prefix length > valid_time -
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valid lifetime > preferred_time - preferred lifetime
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