Note that each time a packet is received, the user registry is refreshed. Look up user id in registry and store resultant user pointer to context.Extract user id from DHCP request and store it to context.Regardless of the protocol type, the process flow upon receipt of an inbound request is the same and is as follows: The library implements callouts for packet receive, subnet select, and packet send for both IPv4 and IPv6. (See user_file.h for more details on file content). UserFile does not enforce any specific content beyond id type and id. Attributes are essentially name/value pairs whose significance is left up to the calling layer. Each entry contains the id type and user id along with optional attributes. UserFile supports reading the registry from a text file in which each line is a user entry in JSON format. Currently, a single implementation has been implemented, user_chk::UserFile. The registry may be manually populated or loaded from a source of data which implements the UserDataSource interface. IPv6 users have a type of 'DUID' and their id is the DUID from the request. IPv4 users have a type of 'HW_ADDR' and their id is the hardware address from the request. UserIds are comprised of data taken from the DHCP request. Users are uniquely identified by their user_chk::UserId. It provides services to load, clear, and refresh the registry as well as to add, find, and remove users.Įach entry in the registry is an instance of the class, user_chk::User. This class represents a maintainable, searchable registry of 'known' users and their attributes. The source code is provided in the src/hooks/dhcp/use_chk directory.Īt the heart of the library is a class hierarchy centered around the class, user_chk::UserRegistry. To provide a real time record of the user registration activity which can be sampled by an external consumer.

To allow DHCP response options or vendor option values to be customized based upon user identity.

To assign 'new' or 'unregistered' users to a restricted subnet, while 'known' or 'registered' users are assigned to unrestricted subnets.

The intent of the custom behavior is three fold: Note that the words 'client' and 'user' are used interchangeably herein.

Specifically it allows subnet selection and DHCP response option customization based upon a registry of DHCP clients. User_chk is an example hooks library which customizes the DHCP query processing provided by Kea DHCP server modules (kea-dhcp4 and kea-dhcp6).

Chk org