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mirror of https://github.com/cwinfo/yggdrasil-go.git synced 2024-12-23 08:45:39 +00:00

Allow multicast to be shut down more sanely

This commit is contained in:
Neil Alexander 2019-09-18 15:31:43 +01:00
parent 00a972b74e
commit 366fe7e772
No known key found for this signature in database
GPG Key ID: A02A2019A2BB0944
2 changed files with 113 additions and 118 deletions

View File

@ -19,14 +19,16 @@ import (
// configured multicast interface, Yggdrasil will attempt to peer with that node
// automatically.
type Multicast struct {
core *yggdrasil.Core
config *config.NodeState
log *log.Logger
sock *ipv6.PacketConn
groupAddr string
listeners map[string]*yggdrasil.TcpListener
listenPort uint16
isOpen bool
core *yggdrasil.Core
config *config.NodeState
log *log.Logger
sock *ipv6.PacketConn
groupAddr string
listeners map[string]*yggdrasil.TcpListener
listenPort uint16
isOpen bool
announcer *time.Timer
platformhandler *time.Timer
}
// Init prepares the multicast interface for use.
@ -63,9 +65,9 @@ func (m *Multicast) Start() error {
}
m.isOpen = true
go m.multicastStarted()
go m.listen()
go m.announce()
m.multicastStarted()
m.announce()
return nil
}
@ -73,6 +75,8 @@ func (m *Multicast) Start() error {
// Stop is not implemented for multicast yet.
func (m *Multicast) Stop() error {
m.isOpen = false
m.announcer.Stop()
m.platformhandler.Stop()
m.sock.Close()
return nil
}
@ -136,108 +140,106 @@ func (m *Multicast) announce() {
if err != nil {
panic(err)
}
for {
interfaces := m.Interfaces()
// 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 {
// Prepare our stop function!
stop := func() {
listener.Stop <- true
delete(m.listeners, name)
m.log.Debugln("No longer multicasting on", name)
}
// If the interface is no longer visible on the system then stop the
// listener, as another one will be started further down
if _, ok := interfaces[name]; !ok {
stop()
continue
}
// It's possible that the link-local listener address has changed so if
// that is the case then we should clean up the interface listener
found := false
listenaddr, err := net.ResolveTCPAddr("tcp6", listener.Listener.Addr().String())
if err != nil {
stop()
continue
}
// Find the interface that matches the listener
if intf, err := net.InterfaceByName(name); err == nil {
if addrs, err := intf.Addrs(); err == nil {
// Loop through the addresses attached to that listener and see if any
// of them match the current address of the listener
for _, addr := range addrs {
if ip, _, err := net.ParseCIDR(addr.String()); err == nil {
// Does the interface address match our listener address?
if ip.Equal(listenaddr.IP) {
found = true
break
}
interfaces := m.Interfaces()
// 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 {
// Prepare our stop function!
stop := func() {
listener.Stop <- true
delete(m.listeners, name)
m.log.Debugln("No longer multicasting on", name)
}
// If the interface is no longer visible on the system then stop the
// listener, as another one will be started further down
if _, ok := interfaces[name]; !ok {
stop()
continue
}
// It's possible that the link-local listener address has changed so if
// that is the case then we should clean up the interface listener
found := false
listenaddr, err := net.ResolveTCPAddr("tcp6", listener.Listener.Addr().String())
if err != nil {
stop()
continue
}
// Find the interface that matches the listener
if intf, err := net.InterfaceByName(name); err == nil {
if addrs, err := intf.Addrs(); err == nil {
// Loop through the addresses attached to that listener and see if any
// of them match the current address of the listener
for _, addr := range addrs {
if ip, _, err := net.ParseCIDR(addr.String()); err == nil {
// Does the interface address match our listener address?
if ip.Equal(listenaddr.IP) {
found = true
break
}
}
}
}
// If the address has not been found on the adapter then we should stop
// and clean up the TCP listener. A new one will be created below if a
// suitable link-local address is found
if !found {
stop()
}
}
// 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 {
panic(err)
}
for _, addr := range addrs {
addrIP, _, _ := net.ParseCIDR(addr.String())
// Ignore IPv4 addresses
if addrIP.To4() != nil {
continue
}
// Ignore non-link-local addresses
if !addrIP.IsLinkLocalUnicast() {
continue
}
// Join the multicast group
m.sock.JoinGroup(&iface, groupAddr)
// Try and see if we already have a TCP listener for this interface
var listener *yggdrasil.TcpListener
if l, ok := m.listeners[iface.Name]; !ok || l.Listener == nil {
// No listener was found - let's create one
listenaddr := fmt.Sprintf("[%s%%%s]:%d", addrIP, iface.Name, m.listenPort)
if li, err := m.core.ListenTCP(listenaddr); err == nil {
m.log.Debugln("Started multicasting on", iface.Name)
// Store the listener so that we can stop it later if needed
m.listeners[iface.Name] = li
listener = li
} else {
m.log.Warnln("Not multicasting on", iface.Name, "due to error:", err)
}
} 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()
if a, err := net.ResolveTCPAddr("tcp6", lladdr); err == nil {
a.Zone = ""
destAddr.Zone = iface.Name
msg := []byte(a.String())
m.sock.WriteTo(msg, nil, destAddr)
}
break
}
// If the address has not been found on the adapter then we should stop
// and clean up the TCP listener. A new one will be created below if a
// suitable link-local address is found
if !found {
stop()
}
time.Sleep(time.Second * 15)
}
// 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 {
panic(err)
}
for _, addr := range addrs {
addrIP, _, _ := net.ParseCIDR(addr.String())
// Ignore IPv4 addresses
if addrIP.To4() != nil {
continue
}
// Ignore non-link-local addresses
if !addrIP.IsLinkLocalUnicast() {
continue
}
// Join the multicast group
m.sock.JoinGroup(&iface, groupAddr)
// Try and see if we already have a TCP listener for this interface
var listener *yggdrasil.TcpListener
if l, ok := m.listeners[iface.Name]; !ok || l.Listener == nil {
// No listener was found - let's create one
listenaddr := fmt.Sprintf("[%s%%%s]:%d", addrIP, iface.Name, m.listenPort)
if li, err := m.core.ListenTCP(listenaddr); err == nil {
m.log.Debugln("Started multicasting on", iface.Name)
// Store the listener so that we can stop it later if needed
m.listeners[iface.Name] = li
listener = li
} else {
m.log.Warnln("Not multicasting on", iface.Name, "due to error:", err)
}
} 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()
if a, err := net.ResolveTCPAddr("tcp6", lladdr); err == nil {
a.Zone = ""
destAddr.Zone = iface.Name
msg := []byte(a.String())
m.sock.WriteTo(msg, nil, destAddr)
}
break
}
}
m.announcer = time.AfterFunc(time.Second*15, m.announce)
}
func (m *Multicast) listen() {

View File

@ -32,21 +32,14 @@ import (
var awdlGoroutineStarted bool
func (m *Multicast) multicastStarted() {
if awdlGoroutineStarted {
return
}
awdlGoroutineStarted = true
for {
C.StopAWDLBrowsing()
for intf := range m.Interfaces() {
if intf == "awdl0" {
m.log.Infoln("Multicast discovery is using AWDL discovery")
C.StartAWDLBrowsing()
break
}
C.StopAWDLBrowsing()
for intf := range m.Interfaces() {
if intf == "awdl0" {
C.StartAWDLBrowsing()
break
}
time.Sleep(time.Minute)
}
m.platformhandler = time.AfterFunc(time.Minute, m.multicastStarted)
}
func (m *Multicast) multicastReuse(network string, address string, c syscall.RawConn) error {