mirror of
https://github.com/linka-cloud/grpc.git
synced 2025-06-22 01:02:29 +00:00
add registry base interface, mdns, noop implementations, add resolver, client
This commit is contained in:
23
registry/mdns/.gitignore
vendored
Normal file
23
registry/mdns/.gitignore
vendored
Normal file
@ -0,0 +1,23 @@
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# Compiled Object files, Static and Dynamic libs (Shared Objects)
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*.o
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*.a
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*.so
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# Folders
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_obj
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_test
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# Architecture specific extensions/prefixes
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*.[568vq]
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[568vq].out
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*.cgo1.go
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*.cgo2.c
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_cgo_defun.c
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_cgo_gotypes.go
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_cgo_export.*
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_testmain.go
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*.exe
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*.test
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508
registry/mdns/client.go
Normal file
508
registry/mdns/client.go
Normal file
@ -0,0 +1,508 @@
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package mdns
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import (
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"context"
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"fmt"
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"log"
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"net"
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"strings"
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"sync"
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"time"
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"github.com/miekg/dns"
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"golang.org/x/net/ipv4"
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"golang.org/x/net/ipv6"
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)
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// ServiceEntry is returned after we query for a service
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type ServiceEntry struct {
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Name string
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Host string
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AddrV4 net.IP
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AddrV6 net.IP
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Port int
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Info string
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InfoFields []string
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TTL int
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Type uint16
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Addr net.IP // @Deprecated
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hasTXT bool
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sent bool
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}
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// complete is used to check if we have all the info we need
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func (s *ServiceEntry) complete() bool {
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return (len(s.AddrV4) > 0 || len(s.AddrV6) > 0 || len(s.Addr) > 0) && s.Port != 0 && s.hasTXT
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}
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// QueryParam is used to customize how a Lookup is performed
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type QueryParam struct {
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Service string // Service to lookup
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Domain string // Lookup domain, default "local"
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Type uint16 // Lookup type, defaults to dns.TypePTR
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Context context.Context // Context
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Timeout time.Duration // Lookup timeout, default 1 second. Ignored if Context is provided
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Interface *net.Interface // Multicast interface to use
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Entries chan<- *ServiceEntry // Entries Channel
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WantUnicastResponse bool // Unicast response desired, as per 5.4 in RFC
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}
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// DefaultParams is used to return a default set of QueryParam's
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func DefaultParams(service string) *QueryParam {
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return &QueryParam{
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Service: service,
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Domain: "local",
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Timeout: time.Second,
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Entries: make(chan *ServiceEntry),
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WantUnicastResponse: false, // TODO(reddaly): Change this default.
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}
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}
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// Query looks up a given service, in a domain, waiting at most
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// for a timeout before finishing the query. The results are streamed
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// to a channel. Sends will not block, so clients should make sure to
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// either read or buffer.
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func Query(params *QueryParam) error {
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// Create a new client
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client, err := newClient()
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if err != nil {
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return err
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}
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defer client.Close()
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// Set the multicast interface
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if params.Interface != nil {
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if err := client.setInterface(params.Interface, false); err != nil {
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return err
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}
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}
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// Ensure defaults are set
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if params.Domain == "" {
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params.Domain = "local"
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}
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if params.Context == nil {
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if params.Timeout == 0 {
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params.Timeout = time.Second
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}
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params.Context, _ = context.WithTimeout(context.Background(), params.Timeout)
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if err != nil {
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return err
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}
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}
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// Run the query
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return client.query(params)
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}
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// Listen listens indefinitely for multicast updates
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func Listen(entries chan<- *ServiceEntry, exit chan struct{}) error {
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// Create a new client
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client, err := newClient()
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if err != nil {
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return err
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}
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defer client.Close()
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client.setInterface(nil, true)
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// Start listening for response packets
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msgCh := make(chan *dns.Msg, 32)
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go client.recv(client.ipv4UnicastConn, msgCh)
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go client.recv(client.ipv6UnicastConn, msgCh)
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go client.recv(client.ipv4MulticastConn, msgCh)
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go client.recv(client.ipv6MulticastConn, msgCh)
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ip := make(map[string]*ServiceEntry)
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for {
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select {
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case <-exit:
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return nil
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case <-client.closedCh:
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return nil
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case m := <-msgCh:
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e := messageToEntry(m, ip)
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if e == nil {
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continue
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}
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// Check if this entry is complete
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if e.complete() {
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if e.sent {
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continue
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}
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e.sent = true
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entries <- e
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ip = make(map[string]*ServiceEntry)
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} else {
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// Fire off a node specific query
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m := new(dns.Msg)
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m.SetQuestion(e.Name, dns.TypePTR)
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m.RecursionDesired = false
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if err := client.sendQuery(m); err != nil {
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log.Printf("[ERR] mdns: Failed to query instance %s: %v", e.Name, err)
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}
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}
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}
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}
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return nil
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}
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// Lookup is the same as Query, however it uses all the default parameters
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func Lookup(service string, entries chan<- *ServiceEntry) error {
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params := DefaultParams(service)
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params.Entries = entries
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return Query(params)
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}
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// Client provides a query interface that can be used to
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// search for service providers using mDNS
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type client struct {
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ipv4UnicastConn *net.UDPConn
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ipv6UnicastConn *net.UDPConn
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ipv4MulticastConn *net.UDPConn
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ipv6MulticastConn *net.UDPConn
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closed bool
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closedCh chan struct{} // TODO(reddaly): This doesn't appear to be used.
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closeLock sync.Mutex
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}
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// NewClient creates a new mdns Client that can be used to query
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// for records
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func newClient() (*client, error) {
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// TODO(reddaly): At least attempt to bind to the port required in the spec.
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// Create a IPv4 listener
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uconn4, err4 := net.ListenUDP("udp4", &net.UDPAddr{IP: net.IPv4zero, Port: 0})
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uconn6, err6 := net.ListenUDP("udp6", &net.UDPAddr{IP: net.IPv6zero, Port: 0})
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if err4 != nil && err6 != nil {
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log.Printf("[ERR] mdns: Failed to bind to udp port: %v %v", err4, err6)
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}
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if uconn4 == nil && uconn6 == nil {
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return nil, fmt.Errorf("failed to bind to any unicast udp port")
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}
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if uconn4 == nil {
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uconn4 = &net.UDPConn{}
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}
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if uconn6 == nil {
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uconn6 = &net.UDPConn{}
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}
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mconn4, err4 := net.ListenUDP("udp4", mdnsWildcardAddrIPv4)
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mconn6, err6 := net.ListenUDP("udp6", mdnsWildcardAddrIPv6)
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if err4 != nil && err6 != nil {
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log.Printf("[ERR] mdns: Failed to bind to udp port: %v %v", err4, err6)
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}
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if mconn4 == nil && mconn6 == nil {
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return nil, fmt.Errorf("failed to bind to any multicast udp port")
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}
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if mconn4 == nil {
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mconn4 = &net.UDPConn{}
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}
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if mconn6 == nil {
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mconn6 = &net.UDPConn{}
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}
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p1 := ipv4.NewPacketConn(mconn4)
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p2 := ipv6.NewPacketConn(mconn6)
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p1.SetMulticastLoopback(true)
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p2.SetMulticastLoopback(true)
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ifaces, err := net.Interfaces()
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if err != nil {
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return nil, err
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}
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var errCount1, errCount2 int
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for _, iface := range ifaces {
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if err := p1.JoinGroup(&iface, &net.UDPAddr{IP: mdnsGroupIPv4}); err != nil {
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errCount1++
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}
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if err := p2.JoinGroup(&iface, &net.UDPAddr{IP: mdnsGroupIPv6}); err != nil {
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errCount2++
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}
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}
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if len(ifaces) == errCount1 && len(ifaces) == errCount2 {
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return nil, fmt.Errorf("Failed to join multicast group on all interfaces!")
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}
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c := &client{
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ipv4MulticastConn: mconn4,
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ipv6MulticastConn: mconn6,
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ipv4UnicastConn: uconn4,
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ipv6UnicastConn: uconn6,
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closedCh: make(chan struct{}),
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}
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return c, nil
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}
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// Close is used to cleanup the client
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func (c *client) Close() error {
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c.closeLock.Lock()
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defer c.closeLock.Unlock()
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if c.closed {
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return nil
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}
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c.closed = true
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close(c.closedCh)
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if c.ipv4UnicastConn != nil {
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c.ipv4UnicastConn.Close()
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}
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if c.ipv6UnicastConn != nil {
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c.ipv6UnicastConn.Close()
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}
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if c.ipv4MulticastConn != nil {
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c.ipv4MulticastConn.Close()
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}
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if c.ipv6MulticastConn != nil {
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c.ipv6MulticastConn.Close()
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}
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return nil
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}
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// setInterface is used to set the query interface, uses sytem
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// default if not provided
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func (c *client) setInterface(iface *net.Interface, loopback bool) error {
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p := ipv4.NewPacketConn(c.ipv4UnicastConn)
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if err := p.JoinGroup(iface, &net.UDPAddr{IP: mdnsGroupIPv4}); err != nil {
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return err
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}
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p2 := ipv6.NewPacketConn(c.ipv6UnicastConn)
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if err := p2.JoinGroup(iface, &net.UDPAddr{IP: mdnsGroupIPv6}); err != nil {
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return err
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}
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p = ipv4.NewPacketConn(c.ipv4MulticastConn)
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if err := p.JoinGroup(iface, &net.UDPAddr{IP: mdnsGroupIPv4}); err != nil {
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return err
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}
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p2 = ipv6.NewPacketConn(c.ipv6MulticastConn)
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if err := p2.JoinGroup(iface, &net.UDPAddr{IP: mdnsGroupIPv6}); err != nil {
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return err
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}
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if loopback {
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p.SetMulticastLoopback(true)
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p2.SetMulticastLoopback(true)
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}
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return nil
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}
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// query is used to perform a lookup and stream results
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func (c *client) query(params *QueryParam) error {
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// Create the service name
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serviceAddr := fmt.Sprintf("%s.%s.", trimDot(params.Service), trimDot(params.Domain))
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// Start listening for response packets
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msgCh := make(chan *dns.Msg, 32)
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go c.recv(c.ipv4UnicastConn, msgCh)
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go c.recv(c.ipv6UnicastConn, msgCh)
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go c.recv(c.ipv4MulticastConn, msgCh)
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go c.recv(c.ipv6MulticastConn, msgCh)
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// Send the query
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m := new(dns.Msg)
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if params.Type == dns.TypeNone {
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m.SetQuestion(serviceAddr, dns.TypePTR)
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} else {
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m.SetQuestion(serviceAddr, params.Type)
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}
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// RFC 6762, section 18.12. Repurposing of Top Bit of qclass in Question
|
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// Section
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//
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// In the Question Section of a Multicast DNS query, the top bit of the qclass
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// field is used to indicate that unicast responses are preferred for this
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// particular question. (See Section 5.4.)
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if params.WantUnicastResponse {
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m.Question[0].Qclass |= 1 << 15
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}
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m.RecursionDesired = false
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if err := c.sendQuery(m); err != nil {
|
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return err
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||||
}
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|
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// Map the in-progress responses
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inprogress := make(map[string]*ServiceEntry)
|
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|
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for {
|
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select {
|
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case resp := <-msgCh:
|
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inp := messageToEntry(resp, inprogress)
|
||||
|
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if inp == nil {
|
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continue
|
||||
}
|
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if len(resp.Question) == 0 || resp.Question[0].Name != m.Question[0].Name {
|
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// discard anything which we've not asked for
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continue
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}
|
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|
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// Check if this entry is complete
|
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if inp.complete() {
|
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if inp.sent {
|
||||
continue
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}
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|
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inp.sent = true
|
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select {
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case params.Entries <- inp:
|
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case <-params.Context.Done():
|
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return nil
|
||||
}
|
||||
} else {
|
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// Fire off a node specific query
|
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m := new(dns.Msg)
|
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m.SetQuestion(inp.Name, inp.Type)
|
||||
m.RecursionDesired = false
|
||||
if err := c.sendQuery(m); err != nil {
|
||||
log.Printf("[ERR] mdns: Failed to query instance %s: %v", inp.Name, err)
|
||||
}
|
||||
}
|
||||
case <-params.Context.Done():
|
||||
return nil
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// sendQuery is used to multicast a query out
|
||||
func (c *client) sendQuery(q *dns.Msg) error {
|
||||
buf, err := q.Pack()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
if c.ipv4UnicastConn != nil {
|
||||
c.ipv4UnicastConn.WriteToUDP(buf, ipv4Addr)
|
||||
}
|
||||
if c.ipv6UnicastConn != nil {
|
||||
c.ipv6UnicastConn.WriteToUDP(buf, ipv6Addr)
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// recv is used to receive until we get a shutdown
|
||||
func (c *client) recv(l *net.UDPConn, msgCh chan *dns.Msg) {
|
||||
if l == nil {
|
||||
return
|
||||
}
|
||||
buf := make([]byte, 65536)
|
||||
for {
|
||||
c.closeLock.Lock()
|
||||
if c.closed {
|
||||
c.closeLock.Unlock()
|
||||
return
|
||||
}
|
||||
c.closeLock.Unlock()
|
||||
n, err := l.Read(buf)
|
||||
if err != nil {
|
||||
continue
|
||||
}
|
||||
msg := new(dns.Msg)
|
||||
if err := msg.Unpack(buf[:n]); err != nil {
|
||||
continue
|
||||
}
|
||||
select {
|
||||
case msgCh <- msg:
|
||||
case <-c.closedCh:
|
||||
return
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// ensureName is used to ensure the named node is in progress
|
||||
func ensureName(inprogress map[string]*ServiceEntry, name string, typ uint16) *ServiceEntry {
|
||||
if inp, ok := inprogress[name]; ok {
|
||||
return inp
|
||||
}
|
||||
inp := &ServiceEntry{
|
||||
Name: name,
|
||||
Type: typ,
|
||||
}
|
||||
inprogress[name] = inp
|
||||
return inp
|
||||
}
|
||||
|
||||
// alias is used to setup an alias between two entries
|
||||
func alias(inprogress map[string]*ServiceEntry, src, dst string, typ uint16) {
|
||||
srcEntry := ensureName(inprogress, src, typ)
|
||||
inprogress[dst] = srcEntry
|
||||
}
|
||||
|
||||
func messageToEntry(m *dns.Msg, inprogress map[string]*ServiceEntry) *ServiceEntry {
|
||||
var inp *ServiceEntry
|
||||
|
||||
for _, answer := range append(m.Answer, m.Extra...) {
|
||||
// TODO(reddaly): Check that response corresponds to serviceAddr?
|
||||
switch rr := answer.(type) {
|
||||
case *dns.PTR:
|
||||
// Create new entry for this
|
||||
inp = ensureName(inprogress, rr.Ptr, rr.Hdr.Rrtype)
|
||||
if inp.complete() {
|
||||
continue
|
||||
}
|
||||
case *dns.SRV:
|
||||
// Check for a target mismatch
|
||||
if rr.Target != rr.Hdr.Name {
|
||||
alias(inprogress, rr.Hdr.Name, rr.Target, rr.Hdr.Rrtype)
|
||||
}
|
||||
|
||||
// Get the port
|
||||
inp = ensureName(inprogress, rr.Hdr.Name, rr.Hdr.Rrtype)
|
||||
if inp.complete() {
|
||||
continue
|
||||
}
|
||||
inp.Host = rr.Target
|
||||
inp.Port = int(rr.Port)
|
||||
case *dns.TXT:
|
||||
// Pull out the txt
|
||||
inp = ensureName(inprogress, rr.Hdr.Name, rr.Hdr.Rrtype)
|
||||
if inp.complete() {
|
||||
continue
|
||||
}
|
||||
inp.Info = strings.Join(rr.Txt, "|")
|
||||
inp.InfoFields = rr.Txt
|
||||
inp.hasTXT = true
|
||||
case *dns.A:
|
||||
// Pull out the IP
|
||||
inp = ensureName(inprogress, rr.Hdr.Name, rr.Hdr.Rrtype)
|
||||
if inp.complete() {
|
||||
continue
|
||||
}
|
||||
inp.Addr = rr.A // @Deprecated
|
||||
inp.AddrV4 = rr.A
|
||||
case *dns.AAAA:
|
||||
// Pull out the IP
|
||||
inp = ensureName(inprogress, rr.Hdr.Name, rr.Hdr.Rrtype)
|
||||
if inp.complete() {
|
||||
continue
|
||||
}
|
||||
inp.Addr = rr.AAAA // @Deprecated
|
||||
inp.AddrV6 = rr.AAAA
|
||||
}
|
||||
|
||||
if inp != nil {
|
||||
inp.TTL = int(answer.Header().Ttl)
|
||||
}
|
||||
}
|
||||
|
||||
return inp
|
||||
}
|
||||
84
registry/mdns/dns_sd.go
Normal file
84
registry/mdns/dns_sd.go
Normal file
@ -0,0 +1,84 @@
|
||||
package mdns
|
||||
|
||||
import "github.com/miekg/dns"
|
||||
|
||||
// DNSSDService is a service that complies with the DNS-SD (RFC 6762) and MDNS
|
||||
// (RFC 6762) specs for local, multicast-DNS-based discovery.
|
||||
//
|
||||
// DNSSDService implements the Zone interface and wraps an MDNSService instance.
|
||||
// To deploy an mDNS service that is compliant with DNS-SD, it's recommended to
|
||||
// register only the wrapped instance with the server.
|
||||
//
|
||||
// Example usage:
|
||||
// service := &mdns.DNSSDService{
|
||||
// MDNSService: &mdns.MDNSService{
|
||||
// Instance: "My Foobar Service",
|
||||
// Service: "_foobar._tcp",
|
||||
// Port: 8000,
|
||||
// }
|
||||
// }
|
||||
// server, err := mdns.NewServer(&mdns.Config{Zone: service})
|
||||
// if err != nil {
|
||||
// log.Fatalf("Error creating server: %v", err)
|
||||
// }
|
||||
// defer server.Shutdown()
|
||||
type DNSSDService struct {
|
||||
MDNSService *MDNSService
|
||||
}
|
||||
|
||||
// Records returns DNS records in response to a DNS question.
|
||||
//
|
||||
// This function returns the DNS response of the underlying MDNSService
|
||||
// instance. It also returns a PTR record for a request for "
|
||||
// _services._dns-sd._udp.<Domain>", as described in section 9 of RFC 6763
|
||||
// ("Service Type Enumeration"), to allow browsing of the underlying MDNSService
|
||||
// instance.
|
||||
func (s *DNSSDService) Records(q dns.Question) []dns.RR {
|
||||
var recs []dns.RR
|
||||
if q.Name == "_services._dns-sd._udp."+s.MDNSService.Domain+"." {
|
||||
recs = s.dnssdMetaQueryRecords(q)
|
||||
}
|
||||
return append(recs, s.MDNSService.Records(q)...)
|
||||
}
|
||||
|
||||
// dnssdMetaQueryRecords returns the DNS records in response to a "meta-query"
|
||||
// issued to browse for DNS-SD services, as per section 9. of RFC6763.
|
||||
//
|
||||
// A meta-query has a name of the form "_services._dns-sd._udp.<Domain>" where
|
||||
// Domain is a fully-qualified domain, such as "local."
|
||||
func (s *DNSSDService) dnssdMetaQueryRecords(q dns.Question) []dns.RR {
|
||||
// Intended behavior, as described in the RFC:
|
||||
// ...it may be useful for network administrators to find the list of
|
||||
// advertised service types on the network, even if those Service Names
|
||||
// are just opaque identifiers and not particularly informative in
|
||||
// isolation.
|
||||
//
|
||||
// For this purpose, a special meta-query is defined. A DNS query for PTR
|
||||
// records with the name "_services._dns-sd._udp.<Domain>" yields a set of
|
||||
// PTR records, where the rdata of each PTR record is the two-abel
|
||||
// <Service> name, plus the same domain, e.g., "_http._tcp.<Domain>".
|
||||
// Including the domain in the PTR rdata allows for slightly better name
|
||||
// compression in Unicast DNS responses, but only the first two labels are
|
||||
// relevant for the purposes of service type enumeration. These two-label
|
||||
// service types can then be used to construct subsequent Service Instance
|
||||
// Enumeration PTR queries, in this <Domain> or others, to discover
|
||||
// instances of that service type.
|
||||
return []dns.RR{
|
||||
&dns.PTR{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: q.Name,
|
||||
Rrtype: dns.TypePTR,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: defaultTTL,
|
||||
},
|
||||
Ptr: s.MDNSService.serviceAddr,
|
||||
},
|
||||
}
|
||||
}
|
||||
|
||||
// Announcement returns DNS records that should be broadcast during the initial
|
||||
// availability of the service, as described in section 8.3 of RFC 6762.
|
||||
// TODO(reddaly): Add this when Announcement is added to the mdns.Zone interface.
|
||||
//func (s *DNSSDService) Announcement() []dns.RR {
|
||||
// return s.MDNSService.Announcement()
|
||||
//}
|
||||
69
registry/mdns/dns_sd_test.go
Normal file
69
registry/mdns/dns_sd_test.go
Normal file
@ -0,0 +1,69 @@
|
||||
package mdns
|
||||
|
||||
import (
|
||||
"reflect"
|
||||
"testing"
|
||||
|
||||
"github.com/miekg/dns"
|
||||
)
|
||||
|
||||
type mockMDNSService struct{}
|
||||
|
||||
func (s *mockMDNSService) Records(q dns.Question) []dns.RR {
|
||||
return []dns.RR{
|
||||
&dns.PTR{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: "fakerecord",
|
||||
Rrtype: dns.TypePTR,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: 42,
|
||||
},
|
||||
Ptr: "fake.local.",
|
||||
},
|
||||
}
|
||||
}
|
||||
|
||||
func (s *mockMDNSService) Announcement() []dns.RR {
|
||||
return []dns.RR{
|
||||
&dns.PTR{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: "fakeannounce",
|
||||
Rrtype: dns.TypePTR,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: 42,
|
||||
},
|
||||
Ptr: "fake.local.",
|
||||
},
|
||||
}
|
||||
}
|
||||
|
||||
func TestDNSSDServiceRecords(t *testing.T) {
|
||||
s := &DNSSDService{
|
||||
MDNSService: &MDNSService{
|
||||
serviceAddr: "_foobar._tcp.local.",
|
||||
Domain: "local",
|
||||
},
|
||||
}
|
||||
q := dns.Question{
|
||||
Name: "_services._dns-sd._udp.local.",
|
||||
Qtype: dns.TypePTR,
|
||||
Qclass: dns.ClassINET,
|
||||
}
|
||||
recs := s.Records(q)
|
||||
if got, want := len(recs), 1; got != want {
|
||||
t.Fatalf("s.Records(%v) returned %v records, want %v", q, got, want)
|
||||
}
|
||||
|
||||
want := dns.RR(&dns.PTR{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: "_services._dns-sd._udp.local.",
|
||||
Rrtype: dns.TypePTR,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: defaultTTL,
|
||||
},
|
||||
Ptr: "_foobar._tcp.local.",
|
||||
})
|
||||
if got := recs[0]; !reflect.DeepEqual(got, want) {
|
||||
t.Errorf("s.Records()[0] = %v, want %v", got, want)
|
||||
}
|
||||
}
|
||||
626
registry/mdns/mdns.go
Normal file
626
registry/mdns/mdns.go
Normal file
@ -0,0 +1,626 @@
|
||||
package mdns
|
||||
|
||||
import (
|
||||
"bytes"
|
||||
"compress/zlib"
|
||||
"context"
|
||||
"encoding/hex"
|
||||
"encoding/json"
|
||||
"fmt"
|
||||
"io/ioutil"
|
||||
"net"
|
||||
"strconv"
|
||||
"strings"
|
||||
"sync"
|
||||
"time"
|
||||
|
||||
"github.com/google/uuid"
|
||||
"google.golang.org/grpc/resolver"
|
||||
|
||||
"gitlab.bertha.cloud/partitio/lab/grpc/registry"
|
||||
resolver2 "gitlab.bertha.cloud/partitio/lab/grpc/resolver"
|
||||
)
|
||||
|
||||
var (
|
||||
// use a .grpc domain rather than .local
|
||||
mdnsDomain = "grpc"
|
||||
)
|
||||
|
||||
type mdnsTxt struct {
|
||||
Service string
|
||||
Version string
|
||||
Metadata map[string]string
|
||||
}
|
||||
|
||||
type mdnsEntry struct {
|
||||
id string
|
||||
node *Server
|
||||
}
|
||||
|
||||
type mdnsRegistry struct {
|
||||
opts registry.Options
|
||||
// the mdns domain
|
||||
domain string
|
||||
|
||||
sync.Mutex
|
||||
services map[string][]*mdnsEntry
|
||||
|
||||
mtx sync.RWMutex
|
||||
|
||||
// watchers
|
||||
watchers map[string]*mdnsWatcher
|
||||
|
||||
// listener
|
||||
listener chan *ServiceEntry
|
||||
}
|
||||
|
||||
func (m *mdnsRegistry) ResolverBuilder() resolver.Builder {
|
||||
return resolver2.New(m)
|
||||
}
|
||||
|
||||
func (m *mdnsRegistry) Scheme() string {
|
||||
panic("implement me")
|
||||
}
|
||||
|
||||
type mdnsWatcher struct {
|
||||
id string
|
||||
wo registry.WatchOptions
|
||||
ch chan *ServiceEntry
|
||||
exit chan struct{}
|
||||
// the mdns domain
|
||||
domain string
|
||||
// the registry
|
||||
registry *mdnsRegistry
|
||||
}
|
||||
|
||||
func encode(txt *mdnsTxt) ([]string, error) {
|
||||
b, err := json.Marshal(txt)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
var buf bytes.Buffer
|
||||
defer buf.Reset()
|
||||
|
||||
w := zlib.NewWriter(&buf)
|
||||
if _, err := w.Write(b); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
w.Close()
|
||||
|
||||
encoded := hex.EncodeToString(buf.Bytes())
|
||||
|
||||
// individual txt limit
|
||||
if len(encoded) <= 255 {
|
||||
return []string{encoded}, nil
|
||||
}
|
||||
|
||||
// split encoded string
|
||||
var record []string
|
||||
|
||||
for len(encoded) > 255 {
|
||||
record = append(record, encoded[:255])
|
||||
encoded = encoded[255:]
|
||||
}
|
||||
|
||||
record = append(record, encoded)
|
||||
|
||||
return record, nil
|
||||
}
|
||||
|
||||
func decode(record []string) (*mdnsTxt, error) {
|
||||
encoded := strings.Join(record, "")
|
||||
|
||||
hr, err := hex.DecodeString(encoded)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
br := bytes.NewReader(hr)
|
||||
zr, err := zlib.NewReader(br)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
rbuf, err := ioutil.ReadAll(zr)
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
var txt *mdnsTxt
|
||||
|
||||
if err := json.Unmarshal(rbuf, &txt); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
return txt, nil
|
||||
}
|
||||
func newRegistry(opts ...registry.Option) registry.Registry {
|
||||
options := registry.Options{
|
||||
Context: context.Background(),
|
||||
Timeout: time.Millisecond * 100,
|
||||
}
|
||||
|
||||
for _, o := range opts {
|
||||
o(&options)
|
||||
}
|
||||
|
||||
// set the domain
|
||||
domain := mdnsDomain
|
||||
|
||||
d, ok := options.Context.Value("domain").(string)
|
||||
if ok {
|
||||
domain = d
|
||||
}
|
||||
|
||||
reg := &mdnsRegistry{
|
||||
opts: options,
|
||||
domain: domain,
|
||||
services: make(map[string][]*mdnsEntry),
|
||||
watchers: make(map[string]*mdnsWatcher),
|
||||
}
|
||||
return reg
|
||||
}
|
||||
|
||||
func (m *mdnsRegistry) Init(opts ...registry.Option) error {
|
||||
for _, o := range opts {
|
||||
o(&m.opts)
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
func (m *mdnsRegistry) Options() registry.Options {
|
||||
return m.opts
|
||||
}
|
||||
|
||||
func (m *mdnsRegistry) Register(service *registry.Service, opts ...registry.RegisterOption) error {
|
||||
m.Lock()
|
||||
defer m.Unlock()
|
||||
|
||||
entries, ok := m.services[service.Name]
|
||||
// first entry, create wildcard used for list queries
|
||||
if !ok {
|
||||
s, err := NewMDNSService(
|
||||
service.Name,
|
||||
"_services",
|
||||
m.domain+".",
|
||||
"",
|
||||
9999,
|
||||
[]net.IP{net.ParseIP("0.0.0.0")},
|
||||
nil,
|
||||
)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
srv, err := NewServer(&Config{Zone: &DNSSDService{MDNSService: s}})
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
// append the wildcard entry
|
||||
entries = append(entries, &mdnsEntry{id: "*", node: srv})
|
||||
}
|
||||
|
||||
var gerr error
|
||||
|
||||
for _, node := range service.Nodes {
|
||||
var seen bool
|
||||
var e *mdnsEntry
|
||||
|
||||
for _, entry := range entries {
|
||||
if node.Id == entry.id {
|
||||
seen = true
|
||||
e = entry
|
||||
break
|
||||
}
|
||||
}
|
||||
|
||||
// already registered, continue
|
||||
if seen {
|
||||
continue
|
||||
// doesn't exist
|
||||
} else {
|
||||
e = &mdnsEntry{}
|
||||
}
|
||||
|
||||
txt, err := encode(&mdnsTxt{
|
||||
Service: service.Name,
|
||||
Version: service.Version,
|
||||
Metadata: node.Metadata,
|
||||
})
|
||||
|
||||
if err != nil {
|
||||
gerr = err
|
||||
continue
|
||||
}
|
||||
|
||||
host, pt, err := net.SplitHostPort(node.Address)
|
||||
if err != nil {
|
||||
gerr = err
|
||||
continue
|
||||
}
|
||||
port, _ := strconv.Atoi(pt)
|
||||
|
||||
// we got here, new node
|
||||
s, err := NewMDNSService(
|
||||
node.Id,
|
||||
service.Name,
|
||||
m.domain+".",
|
||||
"",
|
||||
port,
|
||||
[]net.IP{net.ParseIP(host)},
|
||||
txt,
|
||||
)
|
||||
if err != nil {
|
||||
gerr = err
|
||||
continue
|
||||
}
|
||||
|
||||
srv, err := NewServer(&Config{Zone: s, LocalhostChecking: true})
|
||||
if err != nil {
|
||||
gerr = err
|
||||
continue
|
||||
}
|
||||
|
||||
e.id = node.Id
|
||||
e.node = srv
|
||||
entries = append(entries, e)
|
||||
}
|
||||
|
||||
// save
|
||||
m.services[service.Name] = entries
|
||||
|
||||
return gerr
|
||||
}
|
||||
|
||||
func (m *mdnsRegistry) Deregister(service *registry.Service, opts ...registry.DeregisterOption) error {
|
||||
m.Lock()
|
||||
defer m.Unlock()
|
||||
|
||||
var newEntries []*mdnsEntry
|
||||
|
||||
// loop existing entries, check if any match, shutdown those that do
|
||||
for _, entry := range m.services[service.Name] {
|
||||
var remove bool
|
||||
|
||||
for _, node := range service.Nodes {
|
||||
if node.Id == entry.id {
|
||||
entry.node.Shutdown()
|
||||
remove = true
|
||||
break
|
||||
}
|
||||
}
|
||||
|
||||
// keep it?
|
||||
if !remove {
|
||||
newEntries = append(newEntries, entry)
|
||||
}
|
||||
}
|
||||
|
||||
// last entry is the wildcard for list queries. Remove it.
|
||||
if len(newEntries) == 1 && newEntries[0].id == "*" {
|
||||
newEntries[0].node.Shutdown()
|
||||
delete(m.services, service.Name)
|
||||
} else {
|
||||
m.services[service.Name] = newEntries
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (m *mdnsRegistry) GetService(service string, opts ...registry.GetOption) ([]*registry.Service, error) {
|
||||
serviceMap := make(map[string]*registry.Service)
|
||||
entries := make(chan *ServiceEntry, 10)
|
||||
done := make(chan bool)
|
||||
|
||||
p := DefaultParams(service)
|
||||
// set context with timeout
|
||||
var cancel context.CancelFunc
|
||||
p.Context, cancel = context.WithTimeout(context.Background(), m.opts.Timeout)
|
||||
defer cancel()
|
||||
// set entries channel
|
||||
p.Entries = entries
|
||||
// set the domain
|
||||
p.Domain = m.domain
|
||||
|
||||
go func() {
|
||||
for {
|
||||
select {
|
||||
case e := <-entries:
|
||||
// list record so skip
|
||||
if p.Service == "_services" {
|
||||
continue
|
||||
}
|
||||
if p.Domain != m.domain {
|
||||
continue
|
||||
}
|
||||
if e.TTL == 0 {
|
||||
continue
|
||||
}
|
||||
|
||||
txt, err := decode(e.InfoFields)
|
||||
if err != nil {
|
||||
continue
|
||||
}
|
||||
|
||||
if txt.Service != service {
|
||||
continue
|
||||
}
|
||||
|
||||
s, ok := serviceMap[txt.Version]
|
||||
if !ok {
|
||||
s = ®istry.Service{
|
||||
Name: txt.Service,
|
||||
Version: txt.Version,
|
||||
}
|
||||
}
|
||||
addr := ""
|
||||
// prefer ipv4 addrs
|
||||
if len(e.AddrV4) > 0 {
|
||||
addr = e.AddrV4.String()
|
||||
// else use ipv6
|
||||
} else if len(e.AddrV6) > 0 {
|
||||
addr = "[" + e.AddrV6.String() + "]"
|
||||
} else {
|
||||
continue
|
||||
}
|
||||
s.Nodes = append(s.Nodes, ®istry.Node{
|
||||
Id: strings.TrimSuffix(e.Name, "."+p.Service+"."+p.Domain+"."),
|
||||
Address: fmt.Sprintf("%s:%d", addr, e.Port),
|
||||
Metadata: txt.Metadata,
|
||||
})
|
||||
|
||||
serviceMap[txt.Version] = s
|
||||
case <-p.Context.Done():
|
||||
close(done)
|
||||
return
|
||||
}
|
||||
}
|
||||
}()
|
||||
|
||||
// execute the query
|
||||
if err := Query(p); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
// wait for completion
|
||||
<-done
|
||||
|
||||
// create list and return
|
||||
services := make([]*registry.Service, 0, len(serviceMap))
|
||||
|
||||
for _, service := range serviceMap {
|
||||
services = append(services, service)
|
||||
}
|
||||
|
||||
return services, nil
|
||||
}
|
||||
|
||||
func (m *mdnsRegistry) ListServices(opts ...registry.ListOption) ([]*registry.Service, error) {
|
||||
serviceMap := make(map[string]bool)
|
||||
entries := make(chan *ServiceEntry, 10)
|
||||
done := make(chan bool)
|
||||
|
||||
p := DefaultParams("_services")
|
||||
// set context with timeout
|
||||
var cancel context.CancelFunc
|
||||
p.Context, cancel = context.WithTimeout(context.Background(), m.opts.Timeout)
|
||||
defer cancel()
|
||||
// set entries channel
|
||||
p.Entries = entries
|
||||
// set domain
|
||||
p.Domain = m.domain
|
||||
|
||||
var services []*registry.Service
|
||||
|
||||
go func() {
|
||||
for {
|
||||
select {
|
||||
case e := <-entries:
|
||||
if e.TTL == 0 {
|
||||
continue
|
||||
}
|
||||
if !strings.HasSuffix(e.Name, p.Domain+".") {
|
||||
continue
|
||||
}
|
||||
name := strings.TrimSuffix(e.Name, "."+p.Service+"."+p.Domain+".")
|
||||
if !serviceMap[name] {
|
||||
serviceMap[name] = true
|
||||
services = append(services, ®istry.Service{Name: name})
|
||||
}
|
||||
case <-p.Context.Done():
|
||||
close(done)
|
||||
return
|
||||
}
|
||||
}
|
||||
}()
|
||||
|
||||
// execute query
|
||||
if err := Query(p); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
|
||||
// wait till done
|
||||
<-done
|
||||
|
||||
return services, nil
|
||||
}
|
||||
|
||||
func (m *mdnsRegistry) Watch(opts ...registry.WatchOption) (registry.Watcher, error) {
|
||||
var wo registry.WatchOptions
|
||||
for _, o := range opts {
|
||||
o(&wo)
|
||||
}
|
||||
|
||||
md := &mdnsWatcher{
|
||||
id: uuid.New().String(),
|
||||
wo: wo,
|
||||
ch: make(chan *ServiceEntry, 32),
|
||||
exit: make(chan struct{}),
|
||||
domain: m.domain,
|
||||
registry: m,
|
||||
}
|
||||
|
||||
m.mtx.Lock()
|
||||
defer m.mtx.Unlock()
|
||||
|
||||
// save the watcher
|
||||
m.watchers[md.id] = md
|
||||
|
||||
// check of the listener exists
|
||||
if m.listener != nil {
|
||||
return md, nil
|
||||
}
|
||||
|
||||
// start the listener
|
||||
go func() {
|
||||
// go to infinity
|
||||
for {
|
||||
m.mtx.Lock()
|
||||
|
||||
// just return if there are no watchers
|
||||
if len(m.watchers) == 0 {
|
||||
m.listener = nil
|
||||
m.mtx.Unlock()
|
||||
return
|
||||
}
|
||||
|
||||
// check existing listener
|
||||
if m.listener != nil {
|
||||
m.mtx.Unlock()
|
||||
return
|
||||
}
|
||||
|
||||
// reset the listener
|
||||
exit := make(chan struct{})
|
||||
ch := make(chan *ServiceEntry, 32)
|
||||
m.listener = ch
|
||||
|
||||
m.mtx.Unlock()
|
||||
|
||||
// send messages to the watchers
|
||||
go func() {
|
||||
send := func(w *mdnsWatcher, e *ServiceEntry) {
|
||||
select {
|
||||
case w.ch <- e:
|
||||
default:
|
||||
}
|
||||
}
|
||||
|
||||
for {
|
||||
select {
|
||||
case <-exit:
|
||||
return
|
||||
case e, ok := <-ch:
|
||||
if !ok {
|
||||
return
|
||||
}
|
||||
m.mtx.RLock()
|
||||
// send service entry to all watchers
|
||||
for _, w := range m.watchers {
|
||||
send(w, e)
|
||||
}
|
||||
m.mtx.RUnlock()
|
||||
}
|
||||
}
|
||||
|
||||
}()
|
||||
|
||||
// start listening, blocking call
|
||||
Listen(ch, exit)
|
||||
|
||||
// Listen has unblocked
|
||||
// kill the saved listener
|
||||
m.mtx.Lock()
|
||||
m.listener = nil
|
||||
close(ch)
|
||||
m.mtx.Unlock()
|
||||
}
|
||||
}()
|
||||
|
||||
return md, nil
|
||||
}
|
||||
|
||||
func (m *mdnsRegistry) String() string {
|
||||
return "mdns"
|
||||
}
|
||||
|
||||
func (m *mdnsWatcher) Next() (*registry.Result, error) {
|
||||
for {
|
||||
select {
|
||||
case e := <-m.ch:
|
||||
txt, err := decode(e.InfoFields)
|
||||
if err != nil {
|
||||
continue
|
||||
}
|
||||
|
||||
if len(txt.Service) == 0 || len(txt.Version) == 0 {
|
||||
continue
|
||||
}
|
||||
|
||||
// Filter watch options
|
||||
// wo.Service: Only keep services we care about
|
||||
if len(m.wo.Service) > 0 && txt.Service != m.wo.Service {
|
||||
continue
|
||||
}
|
||||
var action string
|
||||
if e.TTL == 0 {
|
||||
action = "delete"
|
||||
} else {
|
||||
action = "create"
|
||||
}
|
||||
|
||||
service := ®istry.Service{
|
||||
Name: txt.Service,
|
||||
Version: txt.Version,
|
||||
}
|
||||
|
||||
// skip anything without the domain we care about
|
||||
suffix := fmt.Sprintf(".%s.%s.", service.Name, m.domain)
|
||||
if !strings.HasSuffix(e.Name, suffix) {
|
||||
continue
|
||||
}
|
||||
|
||||
var addr string
|
||||
if len(e.AddrV4) > 0 {
|
||||
addr = e.AddrV4.String()
|
||||
} else if len(e.AddrV6) > 0 {
|
||||
addr = "[" + e.AddrV6.String() + "]"
|
||||
} else {
|
||||
addr = e.Addr.String()
|
||||
}
|
||||
|
||||
service.Nodes = append(service.Nodes, ®istry.Node{
|
||||
Id: strings.TrimSuffix(e.Name, suffix),
|
||||
Address: fmt.Sprintf("%s:%d", addr, e.Port),
|
||||
Metadata: txt.Metadata,
|
||||
})
|
||||
|
||||
return ®istry.Result{
|
||||
Action: action,
|
||||
Service: service,
|
||||
}, nil
|
||||
case <-m.exit:
|
||||
return nil, registry.ErrWatcherStopped
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func (m *mdnsWatcher) Stop() {
|
||||
select {
|
||||
case <-m.exit:
|
||||
return
|
||||
default:
|
||||
close(m.exit)
|
||||
// remove self from the registry
|
||||
m.registry.mtx.Lock()
|
||||
delete(m.registry.watchers, m.id)
|
||||
m.registry.mtx.Unlock()
|
||||
}
|
||||
}
|
||||
|
||||
// NewRegistry returns a new default registry which is mdns
|
||||
func NewRegistry(opts ...registry.Option) registry.Registry {
|
||||
return newRegistry(opts...)
|
||||
}
|
||||
32
registry/mdns/mdns_test.go
Normal file
32
registry/mdns/mdns_test.go
Normal file
@ -0,0 +1,32 @@
|
||||
package mdns
|
||||
|
||||
import (
|
||||
"testing"
|
||||
|
||||
"github.com/stretchr/testify/assert"
|
||||
|
||||
"gitlab.bertha.cloud/partitio/lab/grpc/registry"
|
||||
)
|
||||
|
||||
func TestRegistry(t *testing.T) {
|
||||
assert := assert.New(t)
|
||||
reg := NewRegistry()
|
||||
svc := ®istry.Service{Name: "test", Nodes: []*registry.Node{{Id: "test-1", Address: "127.0.0.1:8888"}}}
|
||||
if err := reg.Register(svc); err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
svcs, err := reg.GetService("test")
|
||||
if err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
assert.Len(svcs, 1)
|
||||
assert.Contains(svcs, svc)
|
||||
if err := reg.Deregister(svc); err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
svcs, err = reg.ListServices()
|
||||
if err != nil {
|
||||
t.Fatal(err)
|
||||
}
|
||||
assert.Len(svcs, 0)
|
||||
}
|
||||
517
registry/mdns/server.go
Normal file
517
registry/mdns/server.go
Normal file
@ -0,0 +1,517 @@
|
||||
package mdns
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"math/rand"
|
||||
"net"
|
||||
"sync"
|
||||
"sync/atomic"
|
||||
"time"
|
||||
|
||||
"github.com/miekg/dns"
|
||||
"github.com/sirupsen/logrus"
|
||||
"golang.org/x/net/ipv4"
|
||||
"golang.org/x/net/ipv6"
|
||||
)
|
||||
|
||||
var (
|
||||
mdnsGroupIPv4 = net.ParseIP("224.0.0.251")
|
||||
mdnsGroupIPv6 = net.ParseIP("ff02::fb")
|
||||
|
||||
// mDNS wildcard addresses
|
||||
mdnsWildcardAddrIPv4 = &net.UDPAddr{
|
||||
IP: net.ParseIP("224.0.0.0"),
|
||||
Port: 5353,
|
||||
}
|
||||
mdnsWildcardAddrIPv6 = &net.UDPAddr{
|
||||
IP: net.ParseIP("ff02::"),
|
||||
Port: 5353,
|
||||
}
|
||||
|
||||
// mDNS endpoint addresses
|
||||
ipv4Addr = &net.UDPAddr{
|
||||
IP: mdnsGroupIPv4,
|
||||
Port: 5353,
|
||||
}
|
||||
ipv6Addr = &net.UDPAddr{
|
||||
IP: mdnsGroupIPv6,
|
||||
Port: 5353,
|
||||
}
|
||||
)
|
||||
|
||||
// GetMachineIP is a func which returns the outbound IP of this machine.
|
||||
// Used by the server to determine whether to attempt send the response on a local address
|
||||
type GetMachineIP func() net.IP
|
||||
|
||||
// Config is used to configure the mDNS server
|
||||
type Config struct {
|
||||
// Zone must be provided to support responding to queries
|
||||
Zone Zone
|
||||
|
||||
// Iface if provided binds the multicast listener to the given
|
||||
// interface. If not provided, the system default multicase interface
|
||||
// is used.
|
||||
Iface *net.Interface
|
||||
|
||||
// Port If it is not 0, replace the port 5353 with this port number.
|
||||
Port int
|
||||
|
||||
// GetMachineIP is a function to return the IP of the local machine
|
||||
GetMachineIP GetMachineIP
|
||||
// LocalhostChecking if enabled asks the server to also send responses to 0.0.0.0 if the target IP
|
||||
// is this host (as defined by GetMachineIP). Useful in case machine is on a VPN which blocks comms on non standard ports
|
||||
LocalhostChecking bool
|
||||
}
|
||||
|
||||
// Server is an mDNS server used to listen for mDNS queries and respond if we
|
||||
// have a matching local record
|
||||
type Server struct {
|
||||
config *Config
|
||||
|
||||
ipv4List *net.UDPConn
|
||||
ipv6List *net.UDPConn
|
||||
|
||||
shutdown bool
|
||||
shutdownCh chan struct{}
|
||||
shutdownLock sync.Mutex
|
||||
wg sync.WaitGroup
|
||||
|
||||
outboundIP net.IP
|
||||
}
|
||||
|
||||
// NewServer is used to create a new mDNS server from a config
|
||||
func NewServer(config *Config) (*Server, error) {
|
||||
setCustomPort(config.Port)
|
||||
|
||||
// Create the listeners
|
||||
// Create wildcard connections (because :5353 can be already taken by other apps)
|
||||
ipv4List, _ := net.ListenUDP("udp4", mdnsWildcardAddrIPv4)
|
||||
ipv6List, _ := net.ListenUDP("udp6", mdnsWildcardAddrIPv6)
|
||||
if ipv4List == nil && ipv6List == nil {
|
||||
return nil, fmt.Errorf("[ERR] mdns: Failed to bind to any udp port!")
|
||||
}
|
||||
|
||||
if ipv4List == nil {
|
||||
ipv4List = &net.UDPConn{}
|
||||
}
|
||||
if ipv6List == nil {
|
||||
ipv6List = &net.UDPConn{}
|
||||
}
|
||||
|
||||
// Join multicast groups to receive announcements
|
||||
p1 := ipv4.NewPacketConn(ipv4List)
|
||||
p2 := ipv6.NewPacketConn(ipv6List)
|
||||
p1.SetMulticastLoopback(true)
|
||||
p2.SetMulticastLoopback(true)
|
||||
|
||||
if config.Iface != nil {
|
||||
if err := p1.JoinGroup(config.Iface, &net.UDPAddr{IP: mdnsGroupIPv4}); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
if err := p2.JoinGroup(config.Iface, &net.UDPAddr{IP: mdnsGroupIPv6}); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
} else {
|
||||
ifaces, err := net.Interfaces()
|
||||
if err != nil {
|
||||
return nil, err
|
||||
}
|
||||
errCount1, errCount2 := 0, 0
|
||||
for _, iface := range ifaces {
|
||||
if err := p1.JoinGroup(&iface, &net.UDPAddr{IP: mdnsGroupIPv4}); err != nil {
|
||||
errCount1++
|
||||
}
|
||||
if err := p2.JoinGroup(&iface, &net.UDPAddr{IP: mdnsGroupIPv6}); err != nil {
|
||||
errCount2++
|
||||
}
|
||||
}
|
||||
if len(ifaces) == errCount1 && len(ifaces) == errCount2 {
|
||||
return nil, fmt.Errorf("Failed to join multicast group on all interfaces!")
|
||||
}
|
||||
}
|
||||
|
||||
ipFunc := getOutboundIP
|
||||
if config.GetMachineIP != nil {
|
||||
ipFunc = config.GetMachineIP
|
||||
}
|
||||
|
||||
s := &Server{
|
||||
config: config,
|
||||
ipv4List: ipv4List,
|
||||
ipv6List: ipv6List,
|
||||
shutdownCh: make(chan struct{}),
|
||||
outboundIP: ipFunc(),
|
||||
}
|
||||
|
||||
go s.recv(s.ipv4List)
|
||||
go s.recv(s.ipv6List)
|
||||
|
||||
s.wg.Add(1)
|
||||
go s.probe()
|
||||
|
||||
return s, nil
|
||||
}
|
||||
|
||||
// Shutdown is used to shutdown the listener
|
||||
func (s *Server) Shutdown() error {
|
||||
s.shutdownLock.Lock()
|
||||
defer s.shutdownLock.Unlock()
|
||||
|
||||
if s.shutdown {
|
||||
return nil
|
||||
}
|
||||
|
||||
s.shutdown = true
|
||||
close(s.shutdownCh)
|
||||
s.unregister()
|
||||
|
||||
if s.ipv4List != nil {
|
||||
s.ipv4List.Close()
|
||||
}
|
||||
if s.ipv6List != nil {
|
||||
s.ipv6List.Close()
|
||||
}
|
||||
|
||||
s.wg.Wait()
|
||||
return nil
|
||||
}
|
||||
|
||||
// recv is a long running routine to receive packets from an interface
|
||||
func (s *Server) recv(c *net.UDPConn) {
|
||||
if c == nil {
|
||||
return
|
||||
}
|
||||
buf := make([]byte, 65536)
|
||||
for {
|
||||
s.shutdownLock.Lock()
|
||||
if s.shutdown {
|
||||
s.shutdownLock.Unlock()
|
||||
return
|
||||
}
|
||||
s.shutdownLock.Unlock()
|
||||
n, from, err := c.ReadFrom(buf)
|
||||
if err != nil {
|
||||
continue
|
||||
}
|
||||
if err := s.parsePacket(buf[:n], from); err != nil {
|
||||
logrus.Errorf("[ERR] mdns: Failed to handle query: %v", err)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// parsePacket is used to parse an incoming packet
|
||||
func (s *Server) parsePacket(packet []byte, from net.Addr) error {
|
||||
var msg dns.Msg
|
||||
if err := msg.Unpack(packet); err != nil {
|
||||
logrus.Errorf("[ERR] mdns: Failed to unpack packet: %v", err)
|
||||
return err
|
||||
}
|
||||
// TODO: This is a bit of a hack
|
||||
// We decided to ignore some mDNS answers for the time being
|
||||
// See: https://tools.ietf.org/html/rfc6762#section-7.2
|
||||
msg.Truncated = false
|
||||
return s.handleQuery(&msg, from)
|
||||
}
|
||||
|
||||
// handleQuery is used to handle an incoming query
|
||||
func (s *Server) handleQuery(query *dns.Msg, from net.Addr) error {
|
||||
if query.Opcode != dns.OpcodeQuery {
|
||||
// "In both multicast query and multicast response messages, the OPCODE MUST
|
||||
// be zero on transmission (only standard queries are currently supported
|
||||
// over multicast). Multicast DNS messages received with an OPCODE other
|
||||
// than zero MUST be silently ignored." Note: OpcodeQuery == 0
|
||||
return fmt.Errorf("mdns: received query with non-zero Opcode %v: %v", query.Opcode, *query)
|
||||
}
|
||||
if query.Rcode != 0 {
|
||||
// "In both multicast query and multicast response messages, the Response
|
||||
// Code MUST be zero on transmission. Multicast DNS messages received with
|
||||
// non-zero Response Codes MUST be silently ignored."
|
||||
return fmt.Errorf("mdns: received query with non-zero Rcode %v: %v", query.Rcode, *query)
|
||||
}
|
||||
|
||||
// TODO(reddaly): Handle "TC (Truncated) Bit":
|
||||
// In query messages, if the TC bit is set, it means that additional
|
||||
// Known-Answer records may be following shortly. A responder SHOULD
|
||||
// record this fact, and wait for those additional Known-Answer records,
|
||||
// before deciding whether to respond. If the TC bit is clear, it means
|
||||
// that the querying host has no additional Known Answers.
|
||||
if query.Truncated {
|
||||
return fmt.Errorf("[ERR] mdns: support for DNS requests with high truncated bit not implemented: %v", *query)
|
||||
}
|
||||
|
||||
var unicastAnswer, multicastAnswer []dns.RR
|
||||
|
||||
// Handle each question
|
||||
for _, q := range query.Question {
|
||||
mrecs, urecs := s.handleQuestion(q)
|
||||
multicastAnswer = append(multicastAnswer, mrecs...)
|
||||
unicastAnswer = append(unicastAnswer, urecs...)
|
||||
}
|
||||
|
||||
// See section 18 of RFC 6762 for rules about DNS headers.
|
||||
resp := func(unicast bool) *dns.Msg {
|
||||
// 18.1: ID (Query Identifier)
|
||||
// 0 for multicast response, query.Id for unicast response
|
||||
id := uint16(0)
|
||||
if unicast {
|
||||
id = query.Id
|
||||
}
|
||||
|
||||
var answer []dns.RR
|
||||
if unicast {
|
||||
answer = unicastAnswer
|
||||
} else {
|
||||
answer = multicastAnswer
|
||||
}
|
||||
if len(answer) == 0 {
|
||||
return nil
|
||||
}
|
||||
|
||||
return &dns.Msg{
|
||||
MsgHdr: dns.MsgHdr{
|
||||
Id: id,
|
||||
|
||||
// 18.2: QR (Query/Response) Bit - must be set to 1 in response.
|
||||
Response: true,
|
||||
|
||||
// 18.3: OPCODE - must be zero in response (OpcodeQuery == 0)
|
||||
Opcode: dns.OpcodeQuery,
|
||||
|
||||
// 18.4: AA (Authoritative Answer) Bit - must be set to 1
|
||||
Authoritative: true,
|
||||
|
||||
// The following fields must all be set to 0:
|
||||
// 18.5: TC (TRUNCATED) Bit
|
||||
// 18.6: RD (Recursion Desired) Bit
|
||||
// 18.7: RA (Recursion Available) Bit
|
||||
// 18.8: Z (Zero) Bit
|
||||
// 18.9: AD (Authentic Data) Bit
|
||||
// 18.10: CD (Checking Disabled) Bit
|
||||
// 18.11: RCODE (Response Code)
|
||||
},
|
||||
// 18.12 pertains to questions (handled by handleQuestion)
|
||||
// 18.13 pertains to resource records (handled by handleQuestion)
|
||||
|
||||
// 18.14: Name Compression - responses should be compressed (though see
|
||||
// caveats in the RFC), so set the Compress bit (part of the dns library
|
||||
// API, not part of the DNS packet) to true.
|
||||
Compress: true,
|
||||
Question: query.Question,
|
||||
Answer: answer,
|
||||
}
|
||||
}
|
||||
|
||||
if mresp := resp(false); mresp != nil {
|
||||
if err := s.sendResponse(mresp, from); err != nil {
|
||||
return fmt.Errorf("mdns: error sending multicast response: %v", err)
|
||||
}
|
||||
}
|
||||
if uresp := resp(true); uresp != nil {
|
||||
if err := s.sendResponse(uresp, from); err != nil {
|
||||
return fmt.Errorf("mdns: error sending unicast response: %v", err)
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// handleQuestion is used to handle an incoming question
|
||||
//
|
||||
// The response to a question may be transmitted over multicast, unicast, or
|
||||
// both. The return values are DNS records for each transmission type.
|
||||
func (s *Server) handleQuestion(q dns.Question) (multicastRecs, unicastRecs []dns.RR) {
|
||||
records := s.config.Zone.Records(q)
|
||||
if len(records) == 0 {
|
||||
return nil, nil
|
||||
}
|
||||
|
||||
// Handle unicast and multicast responses.
|
||||
// TODO(reddaly): The decision about sending over unicast vs. multicast is not
|
||||
// yet fully compliant with RFC 6762. For example, the unicast bit should be
|
||||
// ignored if the records in question are close to TTL expiration. For now,
|
||||
// we just use the unicast bit to make the decision, as per the spec:
|
||||
// RFC 6762, section 18.12. Repurposing of Top Bit of qclass in Question
|
||||
// Section
|
||||
//
|
||||
// In the Question Section of a Multicast DNS query, the top bit of the
|
||||
// qclass field is used to indicate that unicast responses are preferred
|
||||
// for this particular question. (See Section 5.4.)
|
||||
if q.Qclass&(1<<15) != 0 {
|
||||
return nil, records
|
||||
}
|
||||
return records, nil
|
||||
}
|
||||
|
||||
func (s *Server) probe() {
|
||||
defer s.wg.Done()
|
||||
|
||||
sd, ok := s.config.Zone.(*MDNSService)
|
||||
if !ok {
|
||||
return
|
||||
}
|
||||
|
||||
name := fmt.Sprintf("%s.%s.%s.", sd.Instance, trimDot(sd.Service), trimDot(sd.Domain))
|
||||
|
||||
q := new(dns.Msg)
|
||||
q.SetQuestion(name, dns.TypePTR)
|
||||
q.RecursionDesired = false
|
||||
|
||||
srv := &dns.SRV{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: name,
|
||||
Rrtype: dns.TypeSRV,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: defaultTTL,
|
||||
},
|
||||
Priority: 0,
|
||||
Weight: 0,
|
||||
Port: uint16(sd.Port),
|
||||
Target: sd.HostName,
|
||||
}
|
||||
txt := &dns.TXT{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: name,
|
||||
Rrtype: dns.TypeTXT,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: defaultTTL,
|
||||
},
|
||||
Txt: sd.TXT,
|
||||
}
|
||||
q.Ns = []dns.RR{srv, txt}
|
||||
|
||||
randomizer := rand.New(rand.NewSource(time.Now().UnixNano()))
|
||||
|
||||
for i := 0; i < 3; i++ {
|
||||
if err := s.SendMulticast(q); err != nil {
|
||||
logrus.Errorf("mdns: failed to send probe: %v", err)
|
||||
}
|
||||
time.Sleep(time.Duration(randomizer.Intn(250)) * time.Millisecond)
|
||||
}
|
||||
|
||||
resp := new(dns.Msg)
|
||||
resp.MsgHdr.Response = true
|
||||
|
||||
// set for query
|
||||
q.SetQuestion(name, dns.TypeANY)
|
||||
|
||||
resp.Answer = append(resp.Answer, s.config.Zone.Records(q.Question[0])...)
|
||||
|
||||
// reset
|
||||
q.SetQuestion(name, dns.TypePTR)
|
||||
|
||||
// From RFC6762
|
||||
// The Multicast DNS responder MUST send at least two unsolicited
|
||||
// responses, one second apart. To provide increased robustness against
|
||||
// packet loss, a responder MAY send up to eight unsolicited responses,
|
||||
// provided that the interval between unsolicited responses increases by
|
||||
// at least a factor of two with every response sent.
|
||||
timeout := 1 * time.Second
|
||||
timer := time.NewTimer(timeout)
|
||||
for i := 0; i < 3; i++ {
|
||||
if err := s.SendMulticast(resp); err != nil {
|
||||
logrus.Errorf("mdns: failed to send announcement: %v", err)
|
||||
}
|
||||
select {
|
||||
case <-timer.C:
|
||||
timeout *= 2
|
||||
timer.Reset(timeout)
|
||||
case <-s.shutdownCh:
|
||||
timer.Stop()
|
||||
return
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// SendMulticast us used to send a multicast response packet
|
||||
func (s *Server) SendMulticast(msg *dns.Msg) error {
|
||||
buf, err := msg.Pack()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
if s.ipv4List != nil {
|
||||
s.ipv4List.WriteToUDP(buf, ipv4Addr)
|
||||
}
|
||||
if s.ipv6List != nil {
|
||||
s.ipv6List.WriteToUDP(buf, ipv6Addr)
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// sendResponse is used to send a response packet
|
||||
func (s *Server) sendResponse(resp *dns.Msg, from net.Addr) error {
|
||||
// TODO(reddaly): Respect the unicast argument, and allow sending responses
|
||||
// over multicast.
|
||||
buf, err := resp.Pack()
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
// Determine the socket to send from
|
||||
addr := from.(*net.UDPAddr)
|
||||
conn := s.ipv4List
|
||||
backupTarget := net.IPv4zero
|
||||
|
||||
if addr.IP.To4() == nil {
|
||||
conn = s.ipv6List
|
||||
backupTarget = net.IPv6zero
|
||||
}
|
||||
_, err = conn.WriteToUDP(buf, addr)
|
||||
// If the address we're responding to is this machine then we can also attempt sending on 0.0.0.0
|
||||
// This covers the case where this machine is using a VPN and certain ports are blocked so the response never gets there
|
||||
// Sending two responses is OK
|
||||
if s.config.LocalhostChecking && addr.IP.Equal(s.outboundIP) {
|
||||
// ignore any errors, this is best efforts
|
||||
conn.WriteToUDP(buf, &net.UDPAddr{IP: backupTarget, Port: addr.Port})
|
||||
}
|
||||
return err
|
||||
|
||||
}
|
||||
|
||||
func (s *Server) unregister() error {
|
||||
sd, ok := s.config.Zone.(*MDNSService)
|
||||
if !ok {
|
||||
return nil
|
||||
}
|
||||
|
||||
atomic.StoreUint32(&sd.TTL, 0)
|
||||
name := fmt.Sprintf("%s.%s.%s.", sd.Instance, trimDot(sd.Service), trimDot(sd.Domain))
|
||||
|
||||
q := new(dns.Msg)
|
||||
q.SetQuestion(name, dns.TypeANY)
|
||||
|
||||
resp := new(dns.Msg)
|
||||
resp.MsgHdr.Response = true
|
||||
resp.Answer = append(resp.Answer, s.config.Zone.Records(q.Question[0])...)
|
||||
|
||||
return s.SendMulticast(resp)
|
||||
}
|
||||
|
||||
func setCustomPort(port int) {
|
||||
if port != 0 {
|
||||
if mdnsWildcardAddrIPv4.Port != port {
|
||||
mdnsWildcardAddrIPv4.Port = port
|
||||
}
|
||||
if mdnsWildcardAddrIPv6.Port != port {
|
||||
mdnsWildcardAddrIPv6.Port = port
|
||||
}
|
||||
if ipv4Addr.Port != port {
|
||||
ipv4Addr.Port = port
|
||||
}
|
||||
if ipv6Addr.Port != port {
|
||||
ipv6Addr.Port = port
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// getOutboundIP returns the IP address of this machine as seen when dialling out
|
||||
func getOutboundIP() net.IP {
|
||||
conn, err := net.Dial("udp", "8.8.8.8:80")
|
||||
if err != nil {
|
||||
// no net connectivity maybe so fallback
|
||||
return nil
|
||||
}
|
||||
defer conn.Close()
|
||||
|
||||
localAddr := conn.LocalAddr().(*net.UDPAddr)
|
||||
|
||||
return localAddr.IP
|
||||
}
|
||||
61
registry/mdns/server_test.go
Normal file
61
registry/mdns/server_test.go
Normal file
@ -0,0 +1,61 @@
|
||||
package mdns
|
||||
|
||||
import (
|
||||
"testing"
|
||||
"time"
|
||||
)
|
||||
|
||||
func TestServer_StartStop(t *testing.T) {
|
||||
s := makeService(t)
|
||||
serv, err := NewServer(&Config{Zone: s, LocalhostChecking: true})
|
||||
if err != nil {
|
||||
t.Fatalf("err: %v", err)
|
||||
}
|
||||
defer serv.Shutdown()
|
||||
}
|
||||
|
||||
func TestServer_Lookup(t *testing.T) {
|
||||
serv, err := NewServer(&Config{Zone: makeServiceWithServiceName(t, "_foobar._tcp"), LocalhostChecking: true})
|
||||
if err != nil {
|
||||
t.Fatalf("err: %v", err)
|
||||
}
|
||||
defer serv.Shutdown()
|
||||
|
||||
entries := make(chan *ServiceEntry, 1)
|
||||
found := false
|
||||
doneCh := make(chan struct{})
|
||||
go func() {
|
||||
select {
|
||||
case e := <-entries:
|
||||
if e.Name != "hostname._foobar._tcp.local." {
|
||||
t.Fatalf("bad: %v", e)
|
||||
}
|
||||
if e.Port != 80 {
|
||||
t.Fatalf("bad: %v", e)
|
||||
}
|
||||
if e.Info != "Local web server" {
|
||||
t.Fatalf("bad: %v", e)
|
||||
}
|
||||
found = true
|
||||
|
||||
case <-time.After(80 * time.Millisecond):
|
||||
t.Fatalf("timeout")
|
||||
}
|
||||
close(doneCh)
|
||||
}()
|
||||
|
||||
params := &QueryParam{
|
||||
Service: "_foobar._tcp",
|
||||
Domain: "local",
|
||||
Timeout: 50 * time.Millisecond,
|
||||
Entries: entries,
|
||||
}
|
||||
err = Query(params)
|
||||
if err != nil {
|
||||
t.Fatalf("err: %v", err)
|
||||
}
|
||||
<-doneCh
|
||||
if !found {
|
||||
t.Fatalf("record not found")
|
||||
}
|
||||
}
|
||||
309
registry/mdns/zone.go
Normal file
309
registry/mdns/zone.go
Normal file
@ -0,0 +1,309 @@
|
||||
package mdns
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"net"
|
||||
"os"
|
||||
"strings"
|
||||
"sync/atomic"
|
||||
|
||||
"github.com/miekg/dns"
|
||||
)
|
||||
|
||||
const (
|
||||
// defaultTTL is the default TTL value in returned DNS records in seconds.
|
||||
defaultTTL = 120
|
||||
)
|
||||
|
||||
// Zone is the interface used to integrate with the server and
|
||||
// to serve records dynamically
|
||||
type Zone interface {
|
||||
// Records returns DNS records in response to a DNS question.
|
||||
Records(q dns.Question) []dns.RR
|
||||
}
|
||||
|
||||
// MDNSService is used to export a named service by implementing a Zone
|
||||
type MDNSService struct {
|
||||
Instance string // Instance name (e.g. "hostService name")
|
||||
Service string // Service name (e.g. "_http._tcp.")
|
||||
Domain string // If blank, assumes "local"
|
||||
HostName string // Host machine DNS name (e.g. "mymachine.net.")
|
||||
Port int // Service Port
|
||||
IPs []net.IP // IP addresses for the service's host
|
||||
TXT []string // Service TXT records
|
||||
TTL uint32
|
||||
serviceAddr string // Fully qualified service address
|
||||
instanceAddr string // Fully qualified instance address
|
||||
enumAddr string // _services._dns-sd._udp.<domain>
|
||||
}
|
||||
|
||||
// validateFQDN returns an error if the passed string is not a fully qualified
|
||||
// hdomain name (more specifically, a hostname).
|
||||
func validateFQDN(s string) error {
|
||||
if len(s) == 0 {
|
||||
return fmt.Errorf("FQDN must not be blank")
|
||||
}
|
||||
if s[len(s)-1] != '.' {
|
||||
return fmt.Errorf("FQDN must end in period: %s", s)
|
||||
}
|
||||
// TODO(reddaly): Perform full validation.
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
// NewMDNSService returns a new instance of MDNSService.
|
||||
//
|
||||
// If domain, hostName, or ips is set to the zero value, then a default value
|
||||
// will be inferred from the operating system.
|
||||
//
|
||||
// TODO(reddaly): This interface may need to change to account for "unique
|
||||
// record" conflict rules of the mDNS protocol. Upon startup, the server should
|
||||
// check to ensure that the instance name does not conflict with other instance
|
||||
// names, and, if required, select a new name. There may also be conflicting
|
||||
// hostName A/AAAA records.
|
||||
func NewMDNSService(instance, service, domain, hostName string, port int, ips []net.IP, txt []string) (*MDNSService, error) {
|
||||
// Sanity check inputs
|
||||
if instance == "" {
|
||||
return nil, fmt.Errorf("missing service instance name")
|
||||
}
|
||||
if service == "" {
|
||||
return nil, fmt.Errorf("missing service name")
|
||||
}
|
||||
if port == 0 {
|
||||
return nil, fmt.Errorf("missing service port")
|
||||
}
|
||||
|
||||
// Set default domain
|
||||
if domain == "" {
|
||||
domain = "local."
|
||||
}
|
||||
if err := validateFQDN(domain); err != nil {
|
||||
return nil, fmt.Errorf("domain %q is not a fully-qualified domain name: %v", domain, err)
|
||||
}
|
||||
|
||||
// Get host information if no host is specified.
|
||||
if hostName == "" {
|
||||
var err error
|
||||
hostName, err = os.Hostname()
|
||||
if err != nil {
|
||||
return nil, fmt.Errorf("could not determine host: %v", err)
|
||||
}
|
||||
hostName = fmt.Sprintf("%s.", hostName)
|
||||
}
|
||||
if err := validateFQDN(hostName); err != nil {
|
||||
return nil, fmt.Errorf("hostName %q is not a fully-qualified domain name: %v", hostName, err)
|
||||
}
|
||||
|
||||
if len(ips) == 0 {
|
||||
var err error
|
||||
ips, err = net.LookupIP(trimDot(hostName))
|
||||
if err != nil {
|
||||
// Try appending the host domain suffix and lookup again
|
||||
// (required for Linux-based hosts)
|
||||
tmpHostName := fmt.Sprintf("%s%s", hostName, domain)
|
||||
|
||||
ips, err = net.LookupIP(trimDot(tmpHostName))
|
||||
|
||||
if err != nil {
|
||||
return nil, fmt.Errorf("could not determine host IP addresses for %s", hostName)
|
||||
}
|
||||
}
|
||||
}
|
||||
for _, ip := range ips {
|
||||
if ip.To4() == nil && ip.To16() == nil {
|
||||
return nil, fmt.Errorf("invalid IP address in IPs list: %v", ip)
|
||||
}
|
||||
}
|
||||
|
||||
return &MDNSService{
|
||||
Instance: instance,
|
||||
Service: service,
|
||||
Domain: domain,
|
||||
HostName: hostName,
|
||||
Port: port,
|
||||
IPs: ips,
|
||||
TXT: txt,
|
||||
TTL: defaultTTL,
|
||||
serviceAddr: fmt.Sprintf("%s.%s.", trimDot(service), trimDot(domain)),
|
||||
instanceAddr: fmt.Sprintf("%s.%s.%s.", instance, trimDot(service), trimDot(domain)),
|
||||
enumAddr: fmt.Sprintf("_services._dns-sd._udp.%s.", trimDot(domain)),
|
||||
}, nil
|
||||
}
|
||||
|
||||
// trimDot is used to trim the dots from the start or end of a string
|
||||
func trimDot(s string) string {
|
||||
return strings.Trim(s, ".")
|
||||
}
|
||||
|
||||
// Records returns DNS records in response to a DNS question.
|
||||
func (m *MDNSService) Records(q dns.Question) []dns.RR {
|
||||
switch q.Name {
|
||||
case m.enumAddr:
|
||||
return m.serviceEnum(q)
|
||||
case m.serviceAddr:
|
||||
return m.serviceRecords(q)
|
||||
case m.instanceAddr:
|
||||
return m.instanceRecords(q)
|
||||
case m.HostName:
|
||||
if q.Qtype == dns.TypeA || q.Qtype == dns.TypeAAAA {
|
||||
return m.instanceRecords(q)
|
||||
}
|
||||
fallthrough
|
||||
default:
|
||||
return nil
|
||||
}
|
||||
}
|
||||
|
||||
func (m *MDNSService) serviceEnum(q dns.Question) []dns.RR {
|
||||
switch q.Qtype {
|
||||
case dns.TypeANY:
|
||||
fallthrough
|
||||
case dns.TypePTR:
|
||||
rr := &dns.PTR{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: q.Name,
|
||||
Rrtype: dns.TypePTR,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: atomic.LoadUint32(&m.TTL),
|
||||
},
|
||||
Ptr: m.serviceAddr,
|
||||
}
|
||||
return []dns.RR{rr}
|
||||
default:
|
||||
return nil
|
||||
}
|
||||
}
|
||||
|
||||
// serviceRecords is called when the query matches the service name
|
||||
func (m *MDNSService) serviceRecords(q dns.Question) []dns.RR {
|
||||
switch q.Qtype {
|
||||
case dns.TypeANY:
|
||||
fallthrough
|
||||
case dns.TypePTR:
|
||||
// Build a PTR response for the service
|
||||
rr := &dns.PTR{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: q.Name,
|
||||
Rrtype: dns.TypePTR,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: atomic.LoadUint32(&m.TTL),
|
||||
},
|
||||
Ptr: m.instanceAddr,
|
||||
}
|
||||
servRec := []dns.RR{rr}
|
||||
|
||||
// Get the instance records
|
||||
instRecs := m.instanceRecords(dns.Question{
|
||||
Name: m.instanceAddr,
|
||||
Qtype: dns.TypeANY,
|
||||
})
|
||||
|
||||
// Return the service record with the instance records
|
||||
return append(servRec, instRecs...)
|
||||
default:
|
||||
return nil
|
||||
}
|
||||
}
|
||||
|
||||
// serviceRecords is called when the query matches the instance name
|
||||
func (m *MDNSService) instanceRecords(q dns.Question) []dns.RR {
|
||||
switch q.Qtype {
|
||||
case dns.TypeANY:
|
||||
// Get the SRV, which includes A and AAAA
|
||||
recs := m.instanceRecords(dns.Question{
|
||||
Name: m.instanceAddr,
|
||||
Qtype: dns.TypeSRV,
|
||||
})
|
||||
|
||||
// Add the TXT record
|
||||
recs = append(recs, m.instanceRecords(dns.Question{
|
||||
Name: m.instanceAddr,
|
||||
Qtype: dns.TypeTXT,
|
||||
})...)
|
||||
return recs
|
||||
|
||||
case dns.TypeA:
|
||||
var rr []dns.RR
|
||||
for _, ip := range m.IPs {
|
||||
if ip4 := ip.To4(); ip4 != nil {
|
||||
rr = append(rr, &dns.A{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: m.HostName,
|
||||
Rrtype: dns.TypeA,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: atomic.LoadUint32(&m.TTL),
|
||||
},
|
||||
A: ip4,
|
||||
})
|
||||
}
|
||||
}
|
||||
return rr
|
||||
|
||||
case dns.TypeAAAA:
|
||||
var rr []dns.RR
|
||||
for _, ip := range m.IPs {
|
||||
if ip.To4() != nil {
|
||||
// TODO(reddaly): IPv4 addresses could be encoded in IPv6 format and
|
||||
// putinto AAAA records, but the current logic puts ipv4-encodable
|
||||
// addresses into the A records exclusively. Perhaps this should be
|
||||
// configurable?
|
||||
continue
|
||||
}
|
||||
|
||||
if ip16 := ip.To16(); ip16 != nil {
|
||||
rr = append(rr, &dns.AAAA{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: m.HostName,
|
||||
Rrtype: dns.TypeAAAA,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: atomic.LoadUint32(&m.TTL),
|
||||
},
|
||||
AAAA: ip16,
|
||||
})
|
||||
}
|
||||
}
|
||||
return rr
|
||||
|
||||
case dns.TypeSRV:
|
||||
// Create the SRV Record
|
||||
srv := &dns.SRV{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: q.Name,
|
||||
Rrtype: dns.TypeSRV,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: atomic.LoadUint32(&m.TTL),
|
||||
},
|
||||
Priority: 10,
|
||||
Weight: 1,
|
||||
Port: uint16(m.Port),
|
||||
Target: m.HostName,
|
||||
}
|
||||
recs := []dns.RR{srv}
|
||||
|
||||
// Add the A record
|
||||
recs = append(recs, m.instanceRecords(dns.Question{
|
||||
Name: m.instanceAddr,
|
||||
Qtype: dns.TypeA,
|
||||
})...)
|
||||
|
||||
// Add the AAAA record
|
||||
recs = append(recs, m.instanceRecords(dns.Question{
|
||||
Name: m.instanceAddr,
|
||||
Qtype: dns.TypeAAAA,
|
||||
})...)
|
||||
return recs
|
||||
|
||||
case dns.TypeTXT:
|
||||
txt := &dns.TXT{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: q.Name,
|
||||
Rrtype: dns.TypeTXT,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: atomic.LoadUint32(&m.TTL),
|
||||
},
|
||||
Txt: m.TXT,
|
||||
}
|
||||
return []dns.RR{txt}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
275
registry/mdns/zone_test.go
Normal file
275
registry/mdns/zone_test.go
Normal file
@ -0,0 +1,275 @@
|
||||
package mdns
|
||||
|
||||
import (
|
||||
"bytes"
|
||||
"net"
|
||||
"reflect"
|
||||
"testing"
|
||||
|
||||
"github.com/miekg/dns"
|
||||
)
|
||||
|
||||
func makeService(t *testing.T) *MDNSService {
|
||||
return makeServiceWithServiceName(t, "_http._tcp")
|
||||
}
|
||||
|
||||
func makeServiceWithServiceName(t *testing.T, service string) *MDNSService {
|
||||
m, err := NewMDNSService(
|
||||
"hostname",
|
||||
service,
|
||||
"local.",
|
||||
"testhost.",
|
||||
80, // port
|
||||
[]net.IP{net.IP([]byte{192, 168, 0, 42}), net.ParseIP("2620:0:1000:1900:b0c2:d0b2:c411:18bc")},
|
||||
[]string{"Local web server"}) // TXT
|
||||
|
||||
if err != nil {
|
||||
t.Fatalf("err: %v", err)
|
||||
}
|
||||
|
||||
return m
|
||||
}
|
||||
|
||||
func TestNewMDNSService_BadParams(t *testing.T) {
|
||||
for _, test := range []struct {
|
||||
testName string
|
||||
hostName string
|
||||
domain string
|
||||
}{
|
||||
{
|
||||
"NewMDNSService should fail when passed hostName that is not a legal fully-qualified domain name",
|
||||
"hostname", // not legal FQDN - should be "hostname." or "hostname.local.", etc.
|
||||
"local.", // legal
|
||||
},
|
||||
{
|
||||
"NewMDNSService should fail when passed domain that is not a legal fully-qualified domain name",
|
||||
"hostname.", // legal
|
||||
"local", // should be "local."
|
||||
},
|
||||
} {
|
||||
_, err := NewMDNSService(
|
||||
"instance name",
|
||||
"_http._tcp",
|
||||
test.domain,
|
||||
test.hostName,
|
||||
80, // port
|
||||
[]net.IP{net.IP([]byte{192, 168, 0, 42})},
|
||||
[]string{"Local web server"}) // TXT
|
||||
if err == nil {
|
||||
t.Fatalf("%s: error expected, but got none", test.testName)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func TestMDNSService_BadAddr(t *testing.T) {
|
||||
s := makeService(t)
|
||||
q := dns.Question{
|
||||
Name: "random",
|
||||
Qtype: dns.TypeANY,
|
||||
}
|
||||
recs := s.Records(q)
|
||||
if len(recs) != 0 {
|
||||
t.Fatalf("bad: %v", recs)
|
||||
}
|
||||
}
|
||||
|
||||
func TestMDNSService_ServiceAddr(t *testing.T) {
|
||||
s := makeService(t)
|
||||
q := dns.Question{
|
||||
Name: "_http._tcp.local.",
|
||||
Qtype: dns.TypeANY,
|
||||
}
|
||||
recs := s.Records(q)
|
||||
if got, want := len(recs), 5; got != want {
|
||||
t.Fatalf("got %d records, want %d: %v", got, want, recs)
|
||||
}
|
||||
|
||||
if ptr, ok := recs[0].(*dns.PTR); !ok {
|
||||
t.Errorf("recs[0] should be PTR record, got: %v, all records: %v", recs[0], recs)
|
||||
} else if got, want := ptr.Ptr, "hostname._http._tcp.local."; got != want {
|
||||
t.Fatalf("bad PTR record %v: got %v, want %v", ptr, got, want)
|
||||
}
|
||||
|
||||
if _, ok := recs[1].(*dns.SRV); !ok {
|
||||
t.Errorf("recs[1] should be SRV record, got: %v, all reccords: %v", recs[1], recs)
|
||||
}
|
||||
if _, ok := recs[2].(*dns.A); !ok {
|
||||
t.Errorf("recs[2] should be A record, got: %v, all records: %v", recs[2], recs)
|
||||
}
|
||||
if _, ok := recs[3].(*dns.AAAA); !ok {
|
||||
t.Errorf("recs[3] should be AAAA record, got: %v, all records: %v", recs[3], recs)
|
||||
}
|
||||
if _, ok := recs[4].(*dns.TXT); !ok {
|
||||
t.Errorf("recs[4] should be TXT record, got: %v, all records: %v", recs[4], recs)
|
||||
}
|
||||
|
||||
q.Qtype = dns.TypePTR
|
||||
if recs2 := s.Records(q); !reflect.DeepEqual(recs, recs2) {
|
||||
t.Fatalf("PTR question should return same result as ANY question: ANY => %v, PTR => %v", recs, recs2)
|
||||
}
|
||||
}
|
||||
|
||||
func TestMDNSService_InstanceAddr_ANY(t *testing.T) {
|
||||
s := makeService(t)
|
||||
q := dns.Question{
|
||||
Name: "hostname._http._tcp.local.",
|
||||
Qtype: dns.TypeANY,
|
||||
}
|
||||
recs := s.Records(q)
|
||||
if len(recs) != 4 {
|
||||
t.Fatalf("bad: %v", recs)
|
||||
}
|
||||
if _, ok := recs[0].(*dns.SRV); !ok {
|
||||
t.Fatalf("bad: %v", recs[0])
|
||||
}
|
||||
if _, ok := recs[1].(*dns.A); !ok {
|
||||
t.Fatalf("bad: %v", recs[1])
|
||||
}
|
||||
if _, ok := recs[2].(*dns.AAAA); !ok {
|
||||
t.Fatalf("bad: %v", recs[2])
|
||||
}
|
||||
if _, ok := recs[3].(*dns.TXT); !ok {
|
||||
t.Fatalf("bad: %v", recs[3])
|
||||
}
|
||||
}
|
||||
|
||||
func TestMDNSService_InstanceAddr_SRV(t *testing.T) {
|
||||
s := makeService(t)
|
||||
q := dns.Question{
|
||||
Name: "hostname._http._tcp.local.",
|
||||
Qtype: dns.TypeSRV,
|
||||
}
|
||||
recs := s.Records(q)
|
||||
if len(recs) != 3 {
|
||||
t.Fatalf("bad: %v", recs)
|
||||
}
|
||||
srv, ok := recs[0].(*dns.SRV)
|
||||
if !ok {
|
||||
t.Fatalf("bad: %v", recs[0])
|
||||
}
|
||||
if _, ok := recs[1].(*dns.A); !ok {
|
||||
t.Fatalf("bad: %v", recs[1])
|
||||
}
|
||||
if _, ok := recs[2].(*dns.AAAA); !ok {
|
||||
t.Fatalf("bad: %v", recs[2])
|
||||
}
|
||||
|
||||
if srv.Port != uint16(s.Port) {
|
||||
t.Fatalf("bad: %v", recs[0])
|
||||
}
|
||||
}
|
||||
|
||||
func TestMDNSService_InstanceAddr_A(t *testing.T) {
|
||||
s := makeService(t)
|
||||
q := dns.Question{
|
||||
Name: "hostname._http._tcp.local.",
|
||||
Qtype: dns.TypeA,
|
||||
}
|
||||
recs := s.Records(q)
|
||||
if len(recs) != 1 {
|
||||
t.Fatalf("bad: %v", recs)
|
||||
}
|
||||
a, ok := recs[0].(*dns.A)
|
||||
if !ok {
|
||||
t.Fatalf("bad: %v", recs[0])
|
||||
}
|
||||
if !bytes.Equal(a.A, []byte{192, 168, 0, 42}) {
|
||||
t.Fatalf("bad: %v", recs[0])
|
||||
}
|
||||
}
|
||||
|
||||
func TestMDNSService_InstanceAddr_AAAA(t *testing.T) {
|
||||
s := makeService(t)
|
||||
q := dns.Question{
|
||||
Name: "hostname._http._tcp.local.",
|
||||
Qtype: dns.TypeAAAA,
|
||||
}
|
||||
recs := s.Records(q)
|
||||
if len(recs) != 1 {
|
||||
t.Fatalf("bad: %v", recs)
|
||||
}
|
||||
a4, ok := recs[0].(*dns.AAAA)
|
||||
if !ok {
|
||||
t.Fatalf("bad: %v", recs[0])
|
||||
}
|
||||
ip6 := net.ParseIP("2620:0:1000:1900:b0c2:d0b2:c411:18bc")
|
||||
if got := len(ip6); got != net.IPv6len {
|
||||
t.Fatalf("test IP failed to parse (len = %d, want %d)", got, net.IPv6len)
|
||||
}
|
||||
if !bytes.Equal(a4.AAAA, ip6) {
|
||||
t.Fatalf("bad: %v", recs[0])
|
||||
}
|
||||
}
|
||||
|
||||
func TestMDNSService_InstanceAddr_TXT(t *testing.T) {
|
||||
s := makeService(t)
|
||||
q := dns.Question{
|
||||
Name: "hostname._http._tcp.local.",
|
||||
Qtype: dns.TypeTXT,
|
||||
}
|
||||
recs := s.Records(q)
|
||||
if len(recs) != 1 {
|
||||
t.Fatalf("bad: %v", recs)
|
||||
}
|
||||
txt, ok := recs[0].(*dns.TXT)
|
||||
if !ok {
|
||||
t.Fatalf("bad: %v", recs[0])
|
||||
}
|
||||
if got, want := txt.Txt, s.TXT; !reflect.DeepEqual(got, want) {
|
||||
t.Fatalf("TXT record mismatch for %v: got %v, want %v", recs[0], got, want)
|
||||
}
|
||||
}
|
||||
|
||||
func TestMDNSService_HostNameQuery(t *testing.T) {
|
||||
s := makeService(t)
|
||||
for _, test := range []struct {
|
||||
q dns.Question
|
||||
want []dns.RR
|
||||
}{
|
||||
{
|
||||
dns.Question{Name: "testhost.", Qtype: dns.TypeA},
|
||||
[]dns.RR{&dns.A{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: "testhost.",
|
||||
Rrtype: dns.TypeA,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: 120,
|
||||
},
|
||||
A: net.IP([]byte{192, 168, 0, 42}),
|
||||
}},
|
||||
},
|
||||
{
|
||||
dns.Question{Name: "testhost.", Qtype: dns.TypeAAAA},
|
||||
[]dns.RR{&dns.AAAA{
|
||||
Hdr: dns.RR_Header{
|
||||
Name: "testhost.",
|
||||
Rrtype: dns.TypeAAAA,
|
||||
Class: dns.ClassINET,
|
||||
Ttl: 120,
|
||||
},
|
||||
AAAA: net.ParseIP("2620:0:1000:1900:b0c2:d0b2:c411:18bc"),
|
||||
}},
|
||||
},
|
||||
} {
|
||||
if got := s.Records(test.q); !reflect.DeepEqual(got, test.want) {
|
||||
t.Errorf("hostname query failed: s.Records(%v) = %v, want %v", test.q, got, test.want)
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func TestMDNSService_serviceEnum_PTR(t *testing.T) {
|
||||
s := makeService(t)
|
||||
q := dns.Question{
|
||||
Name: "_services._dns-sd._udp.local.",
|
||||
Qtype: dns.TypePTR,
|
||||
}
|
||||
recs := s.Records(q)
|
||||
if len(recs) != 1 {
|
||||
t.Fatalf("bad: %v", recs)
|
||||
}
|
||||
if ptr, ok := recs[0].(*dns.PTR); !ok {
|
||||
t.Errorf("recs[0] should be PTR record, got: %v, all records: %v", recs[0], recs)
|
||||
} else if got, want := ptr.Ptr, "_http._tcp.local."; got != want {
|
||||
t.Fatalf("bad PTR record %v: got %v, want %v", ptr, got, want)
|
||||
}
|
||||
}
|
||||
Reference in New Issue
Block a user