mdns

README

mDNS

Name

mDNS - CoreDNS plugin that reads mDNS records from the local network and responds to queries based on those records.

Description

Useful for providing mDNS records to non-mDNS-aware applications by making them accessible through a standard DNS server.

Syntax

mdns example.com [minimum SRV records] [filter text]

Examples

As a prerequisite to using this plugin, there must be systems on the local network broadcasting mDNS records. Note that the .local domain will be replaced with the configured domain. For example, test.local would become test.example.com using the configuration below.

Specify the domain for the records.

example.com {
	mdns example.com
}

And test with dig:

dig @localhost baremetal-test-extra-1.example.com

;; ANSWER SECTION:
baremetal-test-extra-1.example.com. 60 IN A   12.0.0.24
baremetal-test-extra-1.example.com. 60 IN AAAA fe80::f816:3eff:fe49:19b3

If minimum SRV records is specified in the configuration, the plugin will wait until it has at least that many SRV records before responding with any of them. minimum SRV records defaults to 3.

example.com {
    mdns example.com 2
}

This would mean that at least two SRV records of a given type would need to be present for any SRV records to be returned. If only one record is found, any requests for that type of SRV record would receive no results.

If filter text is specified in the configuration, the plugin will ignore any mDNS records that do not include the specified text in the service name. This allows the plugin to be used in environments where there may be mDNS services advertised that are not intended for use with it. When filter text is not set, all records will be processed.

example.com {
    mdns example.com 3 my-id
}

This configuration would ignore any mDNS records that do not contain the string "my-id" in their service name.

Documentation

Index

• func GetIndex(host string) string
• type MDNS
  • func (m MDNS) AddARecord(msg *dns.Msg, state *request.Request, hosts map[string]*zeroconf.ServiceEntry, ...) bool
  • func (m *MDNS) BrowseMDNS()
  • func (m MDNS) Name() string
  • func (m MDNS) ReplaceLocal(input string) string
  • func (m MDNS) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error)
• type ResponsePrinter
  • func NewResponsePrinter(w dns.ResponseWriter) *ResponsePrinter
  • func (r *ResponsePrinter) WriteMsg(res *dns.Msg) error

Functions

func GetIndex

func GetIndex(host string) string

Return the node index from a hostname. For example, the return value from "master-0.ostest.test.metal3.io" would be "0"

Types

type MDNS

type MDNS struct {
	Next   plugin.Handler
	Domain string
	// contains filtered or unexported fields
}

func (MDNS) AddARecord

func (m MDNS) AddARecord(msg *dns.Msg, state *request.Request, hosts map[string]*zeroconf.ServiceEntry, name string) bool

func (*MDNS) BrowseMDNS

func (m *MDNS) BrowseMDNS()

func (MDNS) Name

func (m MDNS) Name() string

func (MDNS) ReplaceLocal

func (m MDNS) ReplaceLocal(input string) string

func (MDNS) ServeDNS

func (m MDNS) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error)

type ResponsePrinter

type ResponsePrinter struct {
	dns.ResponseWriter
}

func NewResponsePrinter

func NewResponsePrinter(w dns.ResponseWriter) *ResponsePrinter

func (*ResponsePrinter) WriteMsg

func (r *ResponsePrinter) WriteMsg(res *dns.Msg) error