feat(discovery): android compatibility
This commit is contained in:
parent
6842d4d88a
commit
33e16c8615
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@ -5,25 +5,30 @@ import (
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"encoding/json"
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"fmt"
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"os"
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"time"
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"forge.cadoles.com/cadoles/go-emlid/reach/discovery"
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"github.com/pkg/errors"
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)
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func main() {
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services, err := discovery.Watch(context.Background())
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resolver := discovery.NewResolver()
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found, err := resolver.Scan(context.Background(), 1*time.Second)
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if err != nil {
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fmt.Printf("[FATAL] %+v", errors.WithStack(err))
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os.Exit(1)
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}
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for srv := range services {
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for srv := range found {
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data, err := json.MarshalIndent(struct {
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Addr string `json:"addr"`
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Name string `json:"name"`
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Addr string `json:"addr"`
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Name string `json:"name"`
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Device string `json:"device"`
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}{
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Name: srv.Name,
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Addr: fmt.Sprintf("%s:%d", srv.AddrV4.String(), srv.Port),
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Name: srv.Name,
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Addr: fmt.Sprintf("%s:%d", srv.AddrV4.String(), srv.Port),
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Device: srv.Device,
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}, "", " ")
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if err != nil {
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fmt.Printf("[FATAL] %+v", errors.WithStack(err))
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8
go.mod
8
go.mod
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@ -14,8 +14,10 @@ require (
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require (
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github.com/cenkalti/backoff v2.2.1+incompatible // indirect
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github.com/gorilla/websocket v1.5.3 // indirect
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github.com/miekg/dns v1.1.27 // indirect
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github.com/hashicorp/mdns v1.0.5 // indirect
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github.com/miekg/dns v1.1.41 // indirect
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github.com/wlynxg/anet v0.0.4-0.20240806025826-e684438fc7c6 // indirect
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golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550 // indirect
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golang.org/x/net v0.0.0-20200114155413-6afb5195e5aa // indirect
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golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe // indirect
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golang.org/x/net v0.0.0-20210410081132-afb366fc7cd1 // indirect
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golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44 // indirect
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)
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21
go.sum
21
go.sum
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@ -12,12 +12,20 @@ github.com/gorilla/websocket v1.5.3 h1:saDtZ6Pbx/0u+bgYQ3q96pZgCzfhKXGPqt7kZ72aN
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github.com/gorilla/websocket v1.5.3/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
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github.com/grandcat/zeroconf v1.0.0 h1:uHhahLBKqwWBV6WZUDAT71044vwOTL+McW0mBJvo6kE=
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github.com/grandcat/zeroconf v1.0.0/go.mod h1:lTKmG1zh86XyCoUeIHSA4FJMBwCJiQmGfcP2PdzytEs=
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github.com/hashicorp/mdns v1.0.5 h1:1M5hW1cunYeoXOqHwEb/GBDDHAFo0Yqb/uz/beC6LbE=
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github.com/hashicorp/mdns v1.0.5/go.mod h1:mtBihi+LeNXGtG8L9dX59gAEa12BDtBQSp4v/YAJqrc=
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github.com/miekg/dns v1.1.27 h1:aEH/kqUzUxGJ/UHcEKdJY+ugH6WEzsEBBSPa8zuy1aM=
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github.com/miekg/dns v1.1.27/go.mod h1:KNUDUusw/aVsxyTYZM1oqvCicbwhgbNgztCETuNZ7xM=
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github.com/miekg/dns v1.1.41 h1:WMszZWJG0XmzbK9FEmzH2TVcqYzFesusSIB41b8KHxY=
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github.com/miekg/dns v1.1.41/go.mod h1:p6aan82bvRIyn+zDIv9xYNUpwa73JcSh9BKwknJysuI=
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github.com/mitchellh/mapstructure v1.5.0 h1:jeMsZIYE/09sWLaz43PL7Gy6RuMjD2eJVyuac5Z2hdY=
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github.com/mitchellh/mapstructure v1.5.0/go.mod h1:bFUtVrKA4DC2yAKiSyO/QUcy7e+RRV2QTWOzhPopBRo=
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github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
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github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
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github.com/wlynxg/anet v0.0.3 h1:PvR53psxFXstc12jelG6f1Lv4MWqE0tI76/hHGjh9rg=
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github.com/wlynxg/anet v0.0.3/go.mod h1:eay5PRQr7fIVAMbTbchTnO9gG65Hg/uYGdc7mguHxoA=
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github.com/wlynxg/anet v0.0.4-0.20240806025826-e684438fc7c6 h1:c/wkXIJvpg2oot7iFqPESTBAO9UvhWTBnW97y9aPgyU=
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github.com/wlynxg/anet v0.0.4-0.20240806025826-e684438fc7c6/go.mod h1:eay5PRQr7fIVAMbTbchTnO9gG65Hg/uYGdc7mguHxoA=
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golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
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golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550 h1:ObdrDkeb4kJdCP557AjRjq69pTHfNouLtWZG7j9rPN8=
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golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
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@ -27,12 +35,25 @@ golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLL
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golang.org/x/net v0.0.0-20190923162816-aa69164e4478/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
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golang.org/x/net v0.0.0-20200114155413-6afb5195e5aa h1:F+8P+gmewFQYRk6JoLQLwjBCTu3mcIURZfNkVweuRKA=
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golang.org/x/net v0.0.0-20200114155413-6afb5195e5aa/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
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golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
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golang.org/x/net v0.0.0-20210410081132-afb366fc7cd1 h1:4qWs8cYYH6PoEFy4dfhDFgoMGkwAcETd+MmPdCPMzUc=
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golang.org/x/net v0.0.0-20210410081132-afb366fc7cd1/go.mod h1:9tjilg8BloeKEkVJvy7fQ90B1CfIiPueXVOjqfkSzI8=
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golang.org/x/sync v0.0.0-20190423024810-112230192c58 h1:8gQV6CLnAEikrhgkHFbMAEhagSSnXWGV915qUMm9mrU=
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golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
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golang.org/x/sync v0.0.0-20210220032951-036812b2e83c h1:5KslGYwFpkhGh+Q16bwMP3cOontH8FOep7tGV86Y7SQ=
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golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
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golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
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golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
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golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe h1:6fAMxZRR6sl1Uq8U61gxU+kPTs2tR8uOySCbBP7BN/M=
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golang.org/x/sys v0.0.0-20190924154521-2837fb4f24fe/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
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golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
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golang.org/x/sys v0.0.0-20210303074136-134d130e1a04/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
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golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44 h1:Bli41pIlzTzf3KEY06n+xnzK/BESIg2ze4Pgfh/aI8c=
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golang.org/x/sys v0.0.0-20210330210617-4fbd30eecc44/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
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golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
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golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
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golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
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golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
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golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
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golang.org/x/tools v0.0.0-20191216052735-49a3e744a425/go.mod h1:TB2adYChydJhpapKDTa4BR/hXlZSLoq2Wpct/0txZ28=
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golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
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@ -1,68 +0,0 @@
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package discovery
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import (
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"context"
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"net"
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"github.com/grandcat/zeroconf"
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"github.com/pkg/errors"
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)
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// Service is a ReachRS service discovered via MDNS-SD
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type Service struct {
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Name string
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AddrV4 *net.IP
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Port int
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}
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// Discover tries to discover ReachRS services on the local network via mDNS-SD
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func Discover(ctx context.Context) ([]Service, error) {
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services := make([]Service, 0)
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watch, err := Watch(ctx)
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if err != nil {
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return nil, errors.WithStack(err)
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}
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for srv := range watch {
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services = append(services, srv)
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}
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return services, nil
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}
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// Watch watches ReachRS services on the local network via mDNS-SD
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func Watch(ctx context.Context) (chan Service, error) {
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out := make(chan Service, 0)
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resolver, err := zeroconf.NewResolver()
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if err != nil {
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return nil, errors.WithStack(err)
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}
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entries := make(chan *zeroconf.ServiceEntry)
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go func() {
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defer close(out)
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for e := range entries {
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var addr *net.IP
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if len(e.AddrIPv4) > 0 {
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addr = &e.AddrIPv4[0]
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}
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srv := Service{
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Name: e.Instance,
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AddrV4: addr,
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Port: e.Port,
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}
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out <- srv
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}
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}()
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if err = resolver.Browse(ctx, "_reach._tcp", ".local", entries); err != nil {
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return nil, err
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}
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return out, nil
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}
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@ -0,0 +1,431 @@
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package mdns
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import (
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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/atomic"
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"time"
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"github.com/miekg/dns"
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"github.com/pkg/errors"
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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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const (
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ipv4mdns = "224.0.0.251"
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ipv6mdns = "ff02::fb"
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mdnsPort = 5353
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forceUnicastResponses = false
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)
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var (
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ipv4Addr = &net.UDPAddr{
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IP: net.ParseIP(ipv4mdns),
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Port: mdnsPort,
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}
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ipv6Addr = &net.UDPAddr{
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IP: net.ParseIP(ipv6mdns),
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Port: mdnsPort,
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}
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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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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 (s.AddrV4 != nil || s.AddrV6 != nil || s.Addr != nil) && 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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Timeout time.Duration // Lookup timeout, default 1 second
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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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DisableIPv4 bool // Whether to disable usage of IPv4 for MDNS operations. Does not affect discovered addresses.
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DisableIPv6 bool // Whether to disable usage of IPv6 for MDNS operations. Does not affect discovered addresses.
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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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DisableIPv4: false,
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DisableIPv6: false,
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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(!params.DisableIPv4, !params.DisableIPv6)
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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); 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.Timeout == 0 {
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params.Timeout = time.Second
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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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// 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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use_ipv4 bool
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use_ipv6 bool
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|
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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 int32
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closedCh chan struct{} // TODO(reddaly): This doesn't appear to be used.
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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(v4 bool, v6 bool) (*client, error) {
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if !v4 && !v6 {
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return nil, fmt.Errorf("Must enable at least one of IPv4 and IPv6 querying")
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}
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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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var uconn4 *net.UDPConn
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var uconn6 *net.UDPConn
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var mconn4 *net.UDPConn
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var mconn6 *net.UDPConn
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var err error
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if v4 {
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uconn4, err = net.ListenUDP("udp4", &net.UDPAddr{IP: net.IPv4zero, Port: 0})
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if err != nil {
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log.Printf("[ERR] mdns: Failed to bind to udp4 port: %+v", errors.WithStack(err))
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}
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}
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if v6 {
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uconn6, err = net.ListenUDP("udp6", &net.UDPAddr{IP: net.IPv6zero, Port: 0})
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if err != nil {
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log.Printf("[ERR] mdns: Failed to bind to udp6 port: %+v", errors.WithStack(err))
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}
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}
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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 v4 {
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mconn4, err = net.ListenMulticastUDP("udp4", nil, ipv4Addr)
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if err != nil {
|
||||
log.Printf("[ERR] mdns: Failed to bind to udp4 port: %+v", errors.WithStack(err))
|
||||
}
|
||||
}
|
||||
if v6 {
|
||||
mconn6, err = net.ListenMulticastUDP("udp6", nil, ipv6Addr)
|
||||
if err != nil {
|
||||
log.Printf("[ERR] mdns: Failed to bind to udp6 port: %+v", errors.WithStack(err))
|
||||
}
|
||||
}
|
||||
|
||||
if mconn4 == nil && mconn6 == nil {
|
||||
return nil, fmt.Errorf("failed to bind to any multicast udp port")
|
||||
}
|
||||
|
||||
c := &client{
|
||||
use_ipv4: v4,
|
||||
use_ipv6: v6,
|
||||
ipv4MulticastConn: mconn4,
|
||||
ipv6MulticastConn: mconn6,
|
||||
ipv4UnicastConn: uconn4,
|
||||
ipv6UnicastConn: uconn6,
|
||||
closedCh: make(chan struct{}),
|
||||
}
|
||||
|
||||
return c, nil
|
||||
}
|
||||
|
||||
// Close is used to cleanup the client
|
||||
func (c *client) Close() error {
|
||||
if !atomic.CompareAndSwapInt32(&c.closed, 0, 1) {
|
||||
// something else already closed it
|
||||
return nil
|
||||
}
|
||||
|
||||
close(c.closedCh)
|
||||
|
||||
if c.ipv4UnicastConn != nil {
|
||||
c.ipv4UnicastConn.Close()
|
||||
}
|
||||
if c.ipv6UnicastConn != nil {
|
||||
c.ipv6UnicastConn.Close()
|
||||
}
|
||||
if c.ipv4MulticastConn != nil {
|
||||
c.ipv4MulticastConn.Close()
|
||||
}
|
||||
if c.ipv6MulticastConn != nil {
|
||||
c.ipv6MulticastConn.Close()
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
// setInterface is used to set the query interface, uses system
|
||||
// default if not provided
|
||||
func (c *client) setInterface(iface *net.Interface) error {
|
||||
if c.use_ipv4 {
|
||||
p := ipv4.NewPacketConn(c.ipv4UnicastConn)
|
||||
if err := p.SetMulticastInterface(iface); err != nil {
|
||||
return err
|
||||
}
|
||||
p = ipv4.NewPacketConn(c.ipv4MulticastConn)
|
||||
if err := p.SetMulticastInterface(iface); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
if c.use_ipv6 {
|
||||
p2 := ipv6.NewPacketConn(c.ipv6UnicastConn)
|
||||
if err := p2.SetMulticastInterface(iface); err != nil {
|
||||
return err
|
||||
}
|
||||
p2 = ipv6.NewPacketConn(c.ipv6MulticastConn)
|
||||
if err := p2.SetMulticastInterface(iface); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// query is used to perform a lookup and stream results
|
||||
func (c *client) query(params *QueryParam) error {
|
||||
// Create the service name
|
||||
serviceAddr := fmt.Sprintf("%s.%s.", trimDot(params.Service), trimDot(params.Domain))
|
||||
|
||||
// Start listening for response packets
|
||||
msgCh := make(chan *dns.Msg, 32)
|
||||
if c.use_ipv4 {
|
||||
go c.recv(c.ipv4UnicastConn, msgCh)
|
||||
go c.recv(c.ipv4MulticastConn, msgCh)
|
||||
}
|
||||
if c.use_ipv6 {
|
||||
go c.recv(c.ipv6UnicastConn, msgCh)
|
||||
go c.recv(c.ipv6MulticastConn, msgCh)
|
||||
}
|
||||
|
||||
// Send the query
|
||||
m := new(dns.Msg)
|
||||
m.SetQuestion(serviceAddr, dns.TypePTR)
|
||||
// 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 params.WantUnicastResponse {
|
||||
m.Question[0].Qclass |= 1 << 15
|
||||
}
|
||||
m.RecursionDesired = false
|
||||
if err := c.sendQuery(m); err != nil {
|
||||
return err
|
||||
}
|
||||
|
||||
// Map the in-progress responses
|
||||
inprogress := make(map[string]*ServiceEntry)
|
||||
|
||||
// Listen until we reach the timeout
|
||||
finish := time.After(params.Timeout)
|
||||
for {
|
||||
select {
|
||||
case resp := <-msgCh:
|
||||
var inp *ServiceEntry
|
||||
for _, answer := range append(resp.Answer, resp.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)
|
||||
|
||||
case *dns.SRV:
|
||||
// Check for a target mismatch
|
||||
if rr.Target != rr.Hdr.Name {
|
||||
alias(inprogress, rr.Hdr.Name, rr.Target)
|
||||
}
|
||||
|
||||
// Get the port
|
||||
inp = ensureName(inprogress, rr.Hdr.Name)
|
||||
inp.Host = rr.Target
|
||||
inp.Port = int(rr.Port)
|
||||
|
||||
case *dns.TXT:
|
||||
// Pull out the txt
|
||||
inp = ensureName(inprogress, rr.Hdr.Name)
|
||||
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)
|
||||
inp.Addr = rr.A // @Deprecated
|
||||
inp.AddrV4 = rr.A
|
||||
|
||||
case *dns.AAAA:
|
||||
// Pull out the IP
|
||||
inp = ensureName(inprogress, rr.Hdr.Name)
|
||||
inp.Addr = rr.AAAA // @Deprecated
|
||||
inp.AddrV6 = rr.AAAA
|
||||
}
|
||||
}
|
||||
|
||||
if inp == nil {
|
||||
continue
|
||||
}
|
||||
|
||||
// Check if this entry is complete
|
||||
if inp.complete() {
|
||||
if inp.sent {
|
||||
continue
|
||||
}
|
||||
inp.sent = true
|
||||
select {
|
||||
case params.Entries <- inp:
|
||||
default:
|
||||
}
|
||||
} else {
|
||||
// Fire off a node specific query
|
||||
m := new(dns.Msg)
|
||||
m.SetQuestion(inp.Name, dns.TypePTR)
|
||||
m.RecursionDesired = false
|
||||
if err := c.sendQuery(m); err != nil {
|
||||
log.Printf("[ERR] mdns: Failed to query instance %s: %+v", inp.Name, errors.WithStack(err))
|
||||
}
|
||||
}
|
||||
case <-finish:
|
||||
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 {
|
||||
_, err = c.ipv4UnicastConn.WriteToUDP(buf, ipv4Addr)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
if c.ipv6UnicastConn != nil {
|
||||
_, err = c.ipv6UnicastConn.WriteToUDP(buf, ipv6Addr)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
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 atomic.LoadInt32(&c.closed) == 0 {
|
||||
n, err := l.Read(buf)
|
||||
|
||||
if atomic.LoadInt32(&c.closed) == 1 {
|
||||
return
|
||||
}
|
||||
|
||||
if err != nil {
|
||||
log.Printf("[ERR] mdns: Failed to read packet: %+v", errors.WithStack(err))
|
||||
continue
|
||||
}
|
||||
msg := new(dns.Msg)
|
||||
if err := msg.Unpack(buf[:n]); err != nil {
|
||||
log.Printf("[ERR] mdns: Failed to unpack packet: %+v", errors.WithStack(err))
|
||||
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) *ServiceEntry {
|
||||
if inp, ok := inprogress[name]; ok {
|
||||
return inp
|
||||
}
|
||||
inp := &ServiceEntry{
|
||||
Name: name,
|
||||
}
|
||||
inprogress[name] = inp
|
||||
return inp
|
||||
}
|
||||
|
||||
// alias is used to setup an alias between two entries
|
||||
func alias(inprogress map[string]*ServiceEntry, src, dst string) {
|
||||
srcEntry := ensureName(inprogress, src)
|
||||
inprogress[dst] = srcEntry
|
||||
}
|
||||
|
||||
// trimDot is used to trim the dots from the start or end of a string
|
||||
func trimDot(s string) string {
|
||||
return strings.Trim(s, ".")
|
||||
}
|
||||
|
|
@ -0,0 +1,228 @@
|
|||
package discovery
|
||||
|
||||
import (
|
||||
"context"
|
||||
"log"
|
||||
"net"
|
||||
"strings"
|
||||
"time"
|
||||
|
||||
"forge.cadoles.com/cadoles/go-emlid/reach/discovery/mdns"
|
||||
"github.com/pkg/errors"
|
||||
"github.com/wlynxg/anet"
|
||||
)
|
||||
|
||||
const ReachService = "_reach._tcp"
|
||||
|
||||
type Resolver struct {
|
||||
}
|
||||
|
||||
func NewResolver() *Resolver {
|
||||
r := &Resolver{}
|
||||
|
||||
return r
|
||||
}
|
||||
|
||||
func (r *Resolver) Scan(ctx context.Context, interval time.Duration) (chan Service, error) {
|
||||
found := make(chan Service)
|
||||
entries := make(chan *mdns.ServiceEntry)
|
||||
|
||||
go r.listener(ctx, entries, found)
|
||||
|
||||
ifaces, err := findMulticastInterfaces(ctx)
|
||||
if err != nil {
|
||||
return nil, errors.WithStack(err)
|
||||
}
|
||||
|
||||
for _, iface := range ifaces {
|
||||
err := func(iface net.Interface) error {
|
||||
hasIPv4, _, err := retrieveSupportedProtocols(iface)
|
||||
if err != nil {
|
||||
return errors.WithStack(err)
|
||||
}
|
||||
|
||||
if !hasIPv4 {
|
||||
return nil
|
||||
}
|
||||
|
||||
err = r.queryIface(entries, iface, interval)
|
||||
if err != nil && !(errors.Is(err, context.DeadlineExceeded) || errors.Is(err, context.Canceled)) {
|
||||
return errors.WithStack(err)
|
||||
}
|
||||
|
||||
go func(iface net.Interface) {
|
||||
defer close(entries)
|
||||
|
||||
if err := r.pollInterface(ctx, entries, iface, interval); err != nil {
|
||||
if err != nil && !(errors.Is(err, context.DeadlineExceeded) || errors.Is(err, context.Canceled)) {
|
||||
log.Printf("[ERROR] %+v", errors.WithStack(err))
|
||||
}
|
||||
}
|
||||
}(iface)
|
||||
|
||||
return nil
|
||||
}(iface)
|
||||
if err != nil {
|
||||
return nil, errors.WithStack(err)
|
||||
}
|
||||
}
|
||||
|
||||
return found, nil
|
||||
}
|
||||
|
||||
func (r *Resolver) queryIface(entries chan *mdns.ServiceEntry, iface net.Interface, timeout time.Duration) error {
|
||||
err := mdns.Query(&mdns.QueryParam{
|
||||
Service: ReachService,
|
||||
Domain: "local",
|
||||
Timeout: timeout,
|
||||
Entries: entries,
|
||||
Interface: &iface,
|
||||
DisableIPv6: true,
|
||||
DisableIPv4: false,
|
||||
})
|
||||
if err != nil {
|
||||
return errors.WithStack(err)
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
|
||||
func (r *Resolver) pollInterface(ctx context.Context, entries chan *mdns.ServiceEntry, iface net.Interface, interval time.Duration) error {
|
||||
ticker := time.NewTicker(interval)
|
||||
for {
|
||||
select {
|
||||
case <-ticker.C:
|
||||
if err := r.queryIface(entries, iface, interval); err != nil {
|
||||
if errors.Is(err, context.DeadlineExceeded) || errors.Is(err, context.Canceled) {
|
||||
continue
|
||||
}
|
||||
|
||||
return errors.WithStack(err)
|
||||
}
|
||||
|
||||
case <-ctx.Done():
|
||||
if err := ctx.Err(); err != nil {
|
||||
return errors.WithStack(err)
|
||||
}
|
||||
|
||||
return nil
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func (r *Resolver) listener(ctx context.Context, entries chan *mdns.ServiceEntry, found chan Service) {
|
||||
defer close(found)
|
||||
|
||||
nameSeparator := "." + ReachService
|
||||
|
||||
for {
|
||||
select {
|
||||
case entry, ok := <-entries:
|
||||
if !ok {
|
||||
return
|
||||
}
|
||||
|
||||
if entry == nil {
|
||||
continue
|
||||
}
|
||||
|
||||
name := strings.Split(entry.Name, nameSeparator)
|
||||
if len(name) < 2 {
|
||||
continue
|
||||
}
|
||||
|
||||
info := decodeTxtRecord(entry.Info)
|
||||
|
||||
srv := Service{
|
||||
Name: name[0],
|
||||
Device: info["device"],
|
||||
AddrV4: entry.AddrV4,
|
||||
Port: entry.Port,
|
||||
}
|
||||
|
||||
found <- srv
|
||||
case <-ctx.Done():
|
||||
return
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
func decodeTxtRecord(txt string) map[string]string {
|
||||
m := make(map[string]string)
|
||||
|
||||
s := strings.Split(txt, "|")
|
||||
for _, v := range s {
|
||||
s := strings.Split(v, "=")
|
||||
if len(s) == 2 {
|
||||
m[s[0]] = s[1]
|
||||
}
|
||||
}
|
||||
|
||||
return m
|
||||
}
|
||||
|
||||
func isIPv4(ip net.IP) bool {
|
||||
return strings.Count(ip.String(), ":") < 2
|
||||
}
|
||||
|
||||
func isIPv6(ip net.IP) bool {
|
||||
return strings.Count(ip.String(), ":") >= 2
|
||||
}
|
||||
|
||||
func findMulticastInterfaces(ctx context.Context) ([]net.Interface, error) {
|
||||
ifaces, err := anet.Interfaces()
|
||||
if err != nil {
|
||||
return nil, nil
|
||||
}
|
||||
|
||||
multicastIfaces := make([]net.Interface, 0)
|
||||
|
||||
for _, iface := range ifaces {
|
||||
if iface.Flags&net.FlagLoopback == net.FlagLoopback {
|
||||
continue
|
||||
}
|
||||
|
||||
if iface.Flags&net.FlagRunning != net.FlagRunning {
|
||||
continue
|
||||
}
|
||||
|
||||
if iface.Flags&net.FlagMulticast != net.FlagMulticast {
|
||||
continue
|
||||
}
|
||||
|
||||
multicastIfaces = append(multicastIfaces, iface)
|
||||
}
|
||||
|
||||
return multicastIfaces, nil
|
||||
}
|
||||
|
||||
func retrieveSupportedProtocols(iface net.Interface) (bool, bool, error) {
|
||||
adresses, err := anet.InterfaceAddrsByInterface(&iface)
|
||||
if err != nil {
|
||||
return false, false, errors.WithStack(err)
|
||||
}
|
||||
|
||||
hasIPv4 := false
|
||||
hasIPv6 := false
|
||||
|
||||
for _, addr := range adresses {
|
||||
ip, _, err := net.ParseCIDR(addr.String())
|
||||
if err != nil {
|
||||
return false, false, errors.WithStack(err)
|
||||
}
|
||||
|
||||
if isIPv4(ip) {
|
||||
hasIPv4 = true
|
||||
}
|
||||
|
||||
if isIPv6(ip) {
|
||||
hasIPv6 = true
|
||||
}
|
||||
|
||||
if hasIPv4 && hasIPv6 {
|
||||
return hasIPv4, hasIPv6, nil
|
||||
}
|
||||
}
|
||||
|
||||
return hasIPv4, hasIPv6, nil
|
||||
}
|
||||
|
|
@ -7,17 +7,33 @@ import (
|
|||
"time"
|
||||
|
||||
"forge.cadoles.com/cadoles/go-emlid/reach"
|
||||
"github.com/davecgh/go-spew/spew"
|
||||
"github.com/pkg/errors"
|
||||
)
|
||||
|
||||
func TestDiscovery(t *testing.T) {
|
||||
func TestResolver(t *testing.T) {
|
||||
reach.AssertIntegrationTests(t)
|
||||
|
||||
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
|
||||
defer cancel()
|
||||
|
||||
services, err := Discover(ctx)
|
||||
resolver := NewResolver()
|
||||
|
||||
found, err := resolver.Scan(ctx, 500*time.Millisecond)
|
||||
if err != nil {
|
||||
t.Fatal(err)
|
||||
t.Fatalf("%+v", errors.WithStack(err))
|
||||
}
|
||||
|
||||
services := make([]Service, 0)
|
||||
OUTER:
|
||||
for {
|
||||
select {
|
||||
case s := <-found:
|
||||
t.Logf("%s", spew.Sdump(s))
|
||||
services = append(services, s)
|
||||
case <-ctx.Done():
|
||||
break OUTER
|
||||
}
|
||||
}
|
||||
|
||||
if g, e := len(services), 1; g < e {
|
||||
|
|
@ -0,0 +1,10 @@
|
|||
package discovery
|
||||
|
||||
import "net"
|
||||
|
||||
type Service struct {
|
||||
Name string
|
||||
Device string
|
||||
AddrV4 net.IP
|
||||
Port int
|
||||
}
|
||||
Loading…
Reference in New Issue