Files
tendrils/dante.go
2026-01-23 09:12:09 -08:00

153 lines
2.9 KiB
Go

package tendrils
import (
"context"
"log"
"net"
"time"
"github.com/miekg/dns"
)
func (t *Tendrils) listenDante(ctx context.Context, iface net.Interface) {
go t.queryDanteMDNS(ctx, iface)
go t.listenPTP(ctx, iface)
}
func (t *Tendrils) queryDanteMDNS(ctx context.Context, iface net.Interface) {
addrs, err := iface.Addrs()
if err != nil {
return
}
var srcIP net.IP
for _, addr := range addrs {
if ipnet, ok := addr.(*net.IPNet); ok && ipnet.IP.To4() != nil {
srcIP = ipnet.IP.To4()
break
}
}
if srcIP == nil {
return
}
ticker := time.NewTicker(30 * time.Second)
defer ticker.Stop()
t.sendDanteMDNSQuery(iface.Name, srcIP)
for {
select {
case <-ctx.Done():
return
case <-ticker.C:
t.sendDanteMDNSQuery(iface.Name, srcIP)
}
}
}
func (t *Tendrils) sendDanteMDNSQuery(ifaceName string, srcIP net.IP) {
conn, err := net.DialUDP("udp4", &net.UDPAddr{IP: srcIP}, &net.UDPAddr{IP: net.IPv4(224, 0, 0, 251), Port: 5353})
if err != nil {
return
}
defer conn.Close()
services := []string{
"_netaudio-arc._udp.local.",
"_netaudio-cmc._udp.local.",
"_netaudio-dbc._udp.local.",
"_netaudio-chan._udp.local.",
"_dantevideo._udp.local.",
"_danteancil._udp.local.",
}
for _, service := range services {
msg := new(dns.Msg)
msg.SetQuestion(service, dns.TypePTR)
msg.RecursionDesired = false
data, err := msg.Pack()
if err != nil {
continue
}
conn.Write(data)
}
if t.DebugDante {
log.Printf("[dante] %s: sent mdns queries for netaudio services", ifaceName)
}
}
func (t *Tendrils) listenPTP(ctx context.Context, iface net.Interface) {
addr, err := net.ResolveUDPAddr("udp4", "224.0.1.129:319")
if err != nil {
return
}
conn, err := net.ListenMulticastUDP("udp4", &iface, addr)
if err != nil {
if t.DebugDante {
log.Printf("[dante] %s: failed to listen ptp: %v", iface.Name, err)
}
return
}
defer conn.Close()
buf := make([]byte, 1500)
for {
select {
case <-ctx.Done():
return
default:
}
conn.SetReadDeadline(time.Now().Add(1 * time.Second))
n, src, err := conn.ReadFromUDP(buf)
if err != nil {
if netErr, ok := err.(net.Error); ok && netErr.Timeout() {
continue
}
continue
}
t.handlePTPPacket(iface.Name, src.IP, buf[:n])
}
}
func (t *Tendrils) handlePTPPacket(ifaceName string, srcIP net.IP, data []byte) {
if len(data) < 34 {
return
}
messageType := data[0] & 0x0f
if messageType != 0x0b {
return
}
if len(data) < 64 {
return
}
clockClass := data[48]
clockAccuracy := data[49]
priority1 := data[47]
priority2 := data[51]
if t.DebugDante {
log.Printf("[dante] %s: ptp announce from %s class=%d accuracy=%d p1=%d p2=%d",
ifaceName, srcIP, clockClass, clockAccuracy, priority1, priority2)
}
t.nodes.SetDanteClockMaster(srcIP)
}
func (n *Nodes) UpdateDante(name string, ip net.IP) {
if n.t.DebugDante {
log.Printf("[dante] mdns response: %s -> %s", name, ip)
}
n.Update(nil, nil, []net.IP{ip}, "", name, "dante")
}