yggdrasil-network/yggdrasil-go
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Properly handle multicast interfaces going up and down

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This commit is contained in:
Neil Alexander 2019-03-06 12:07:33 +00:00
parent cc0c725e63
commit f4e17b9a9f
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GPG key ID: A02A2019A2BB0944
3 changed files with 57 additions and 37 deletions
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37
src/yggdrasil/multicast.go
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@ -64,13 +64,13 @@ func (m *multicast) start() error {
return nil
}
func (m *multicast) interfaces() []net.Interface {
func (m *multicast) interfaces() map[string]net.Interface {
// Get interface expressions from config
m.core.configMutex.RLock()
exprs := m.core.config.MulticastInterfaces
m.core.configMutex.RUnlock()
// Ask the system for network interfaces
var interfaces []net.Interface
interfaces := make(map[string]net.Interface)
allifaces, err := net.Interfaces()
if err != nil {
panic(err)
@ -97,7 +97,7 @@ func (m *multicast) interfaces() []net.Interface {
}
// Does the interface match the regular expression? Store it if so
if e.MatchString(iface.Name) {
interfaces = append(interfaces, iface)
interfaces[iface.Name] = iface
}
}
}
@ -114,7 +114,10 @@ func (m *multicast) announce() {
panic(err)
}
for {
for _, iface := range m.interfaces() {
interfaces := m.interfaces()
// Now that we have a list of valid interfaces from the operating system,
// we can start checking if we can send multicasts on them
for _, iface := range interfaces {
// Find interface addresses
addrs, err := iface.Addrs()
if err != nil {
@ -134,23 +137,24 @@ func (m *multicast) announce() {
m.sock.JoinGroup(&iface, groupAddr)
// Try and see if we already have a TCP listener for this interface
var listener *tcpListener
if _, ok := m.listeners[iface.Name]; !ok {
if l, ok := m.listeners[iface.Name]; !ok || l.listener == nil {
// No listener was found - let's create one
listenaddr := fmt.Sprintf("[%s%%%s]:0", addrIP, iface.Name)
if l, err := m.core.link.tcp.listen(listenaddr); err == nil {
m.core.log.Debugln("Started multicasting on", iface.Name)
// Store the listener so that we can stop it later if needed
listener = &tcpListener{
listener: l,
stop: make(chan bool),
}
m.listeners[iface.Name] = listener
m.listeners[iface.Name] = l
}
} else {
// An existing listener was found
listener = m.listeners[iface.Name]
}
// Make sure nothing above failed for some reason
if listener == nil {
continue
}
// Get the listener details and construct the multicast beacon
lladdr := (*listener.listener).Addr().String()
lladdr := listener.listener.Addr().String()
if a, err := net.ResolveTCPAddr("tcp6", lladdr); err == nil {
destAddr.Zone = iface.Name
msg := []byte(a.String())
@ -160,7 +164,16 @@ func (m *multicast) announce() {
}
time.Sleep(time.Second)
}
time.Sleep(time.Second)
// There might be interfaces that we configured listeners for but are no
// longer up - if that's the case then we should stop the listeners
for name, listener := range m.listeners {
if _, ok := interfaces[name]; !ok {
listener.stop <- true
delete(m.listeners, name)
m.core.log.Debugln("No longer multicasting on", name)
}
}
time.Sleep(time.Second * 5)
}
}