From 54f1804101ff45e0b02580a17edaeab882beb21f Mon Sep 17 00:00:00 2001 From: Neil Alexander Date: Thu, 20 Jun 2019 15:11:55 +0100 Subject: [PATCH] Try and solidify multicast interface behavior --- src/multicast/admin.go | 2 +- src/multicast/multicast.go | 143 +++++++++++++++--------------- src/multicast/multicast_darwin.go | 4 +- 3 files changed, 76 insertions(+), 73 deletions(-) diff --git a/src/multicast/admin.go b/src/multicast/admin.go index 672b7ca4..40e28af4 100644 --- a/src/multicast/admin.go +++ b/src/multicast/admin.go @@ -5,7 +5,7 @@ import "github.com/yggdrasil-network/yggdrasil-go/src/admin" func (m *Multicast) SetupAdminHandlers(a *admin.AdminSocket) { a.AddHandler("getMulticastInterfaces", []string{}, func(in admin.Info) (admin.Info, error) { var intfs []string - for _, v := range m.interfaces() { + for _, v := range m.GetInterfaces() { intfs = append(intfs, v.Name) } return admin.Info{"multicast_interfaces": intfs}, nil diff --git a/src/multicast/multicast.go b/src/multicast/multicast.go index cbde7fd9..f0b1a9a1 100644 --- a/src/multicast/multicast.go +++ b/src/multicast/multicast.go @@ -5,6 +5,7 @@ import ( "fmt" "net" "regexp" + "sync" "time" "github.com/gologme/log" @@ -19,14 +20,16 @@ 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 - reconfigure chan chan error - sock *ipv6.PacketConn - groupAddr string - listeners map[string]*yggdrasil.TcpListener - listenPort uint16 + core *yggdrasil.Core + config *config.NodeState + log *log.Logger + sock *ipv6.PacketConn + groupAddr string + listeners map[string]*yggdrasil.TcpListener + listenPort uint16 + interfaces map[string]net.Interface + interfacesMutex sync.RWMutex + interfacesTime time.Time } // Init prepares the multicast interface for use. @@ -34,25 +37,24 @@ func (m *Multicast) Init(core *yggdrasil.Core, state *config.NodeState, log *log m.core = core m.config = state m.log = log - m.reconfigure = make(chan chan error, 1) m.listeners = make(map[string]*yggdrasil.TcpListener) + m.interfaces = make(map[string]net.Interface) current, _ := m.config.Get() m.listenPort = current.LinkLocalTCPPort + m.groupAddr = "[ff02::114]:9001" + // Perform our first check for multicast interfaces + if count := m.UpdateInterfaces(); count != 0 { + m.log.Infoln("Found", count, "multicast interface(s)") + } else { + m.log.Infoln("Multicast is not enabled on any interfaces") + } + // Keep checking quietly every minute in case they change go func() { for { - e := <-m.reconfigure - // There's nothing particularly to do here because the multicast module - // already consults the config.NodeState when enumerating multicast - // interfaces on each pass. We just need to return nil so that the - // reconfiguration doesn't block indefinitely - e <- nil + time.Sleep(time.Minute) + m.UpdateInterfaces() } }() - m.groupAddr = "[ff02::114]:9001" - // Check if we've been given any expressions - if count := len(m.interfaces()); count != 0 { - m.log.Infoln("Found", count, "multicast interface(s)") - } return nil } @@ -60,32 +62,27 @@ func (m *Multicast) Init(core *yggdrasil.Core, state *config.NodeState, log *log // listen for multicast beacons from other hosts and will advertise multicast // beacons out to the network. func (m *Multicast) Start() error { - current, _ := m.config.Get() - if len(current.MulticastInterfaces) == 0 { - m.log.Infoln("Multicast discovery is disabled") - } else { - m.log.Infoln("Multicast discovery is enabled") - addr, err := net.ResolveUDPAddr("udp", m.groupAddr) - if err != nil { - return err - } - listenString := fmt.Sprintf("[::]:%v", addr.Port) - lc := net.ListenConfig{ - Control: m.multicastReuse, - } - conn, err := lc.ListenPacket(context.Background(), "udp6", listenString) - if err != nil { - return err - } - m.sock = ipv6.NewPacketConn(conn) - if err = m.sock.SetControlMessage(ipv6.FlagDst, true); err != nil { - // Windows can't set this flag, so we need to handle it in other ways - } - - go m.multicastStarted() - go m.listen() - go m.announce() + addr, err := net.ResolveUDPAddr("udp", m.groupAddr) + if err != nil { + return err } + listenString := fmt.Sprintf("[::]:%v", addr.Port) + lc := net.ListenConfig{ + Control: m.multicastReuse, + } + conn, err := lc.ListenPacket(context.Background(), "udp6", listenString) + if err != nil { + return err + } + m.sock = ipv6.NewPacketConn(conn) + if err = m.sock.SetControlMessage(ipv6.FlagDst, true); err != nil { + // Windows can't set this flag, so we need to handle it in other ways + } + + go m.multicastStarted() + go m.listen() + go m.announce() + return nil } @@ -102,34 +99,37 @@ func (m *Multicast) UpdateConfig(config *config.NodeConfig) { m.config.Replace(*config) - errors := 0 + m.log.Infoln("Multicast configuration reloaded successfully") - components := []chan chan error{ - m.reconfigure, - } - - for _, component := range components { - response := make(chan error) - component <- response - if err := <-response; err != nil { - m.log.Errorln(err) - errors++ - } - } - - if errors > 0 { - m.log.Warnln(errors, "multicast module(s) reported errors during configuration reload") + if count := m.UpdateInterfaces(); count != 0 { + m.log.Infoln("Found", count, "multicast interface(s)") } else { - m.log.Infoln("Multicast configuration reloaded successfully") + m.log.Infoln("Multicast is not enabled on any interfaces") } } -func (m *Multicast) interfaces() map[string]net.Interface { +// GetInterfaces returns the currently known/enabled multicast interfaces. It is +// expected that UpdateInterfaces has been called at least once before calling +// this method. +func (m *Multicast) GetInterfaces() map[string]net.Interface { + m.interfacesMutex.RLock() + defer m.interfacesMutex.RUnlock() + return m.interfaces +} + +// UpdateInterfaces re-enumerates the available multicast interfaces on the +// system, using the current MulticastInterfaces config option as a template. +// The number of selected interfaces is returned. +func (m *Multicast) UpdateInterfaces() int { + m.interfacesMutex.Lock() + defer m.interfacesMutex.Unlock() // Get interface expressions from config current, _ := m.config.Get() exprs := current.MulticastInterfaces // Ask the system for network interfaces - interfaces := make(map[string]net.Interface) + for i := range m.interfaces { + delete(m.interfaces, i) + } allifaces, err := net.Interfaces() if err != nil { panic(err) @@ -156,11 +156,12 @@ func (m *Multicast) interfaces() map[string]net.Interface { } // Does the interface match the regular expression? Store it if so if e.MatchString(iface.Name) { - interfaces[iface.Name] = iface + m.interfaces[iface.Name] = iface } } } - return interfaces + m.interfacesTime = time.Now() + return len(m.interfaces) } func (m *Multicast) announce() { @@ -173,7 +174,7 @@ func (m *Multicast) announce() { panic(err) } for { - interfaces := m.interfaces() + interfaces := m.GetInterfaces() // 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 { @@ -307,9 +308,11 @@ func (m *Multicast) listen() { if addr.IP.String() != from.IP.String() { continue } - addr.Zone = "" - if err := m.core.CallPeer("tcp://"+addr.String(), from.Zone); err != nil { - m.log.Debugln("Call from multicast failed:", err) + if _, ok := m.GetInterfaces()[from.Zone]; ok { + addr.Zone = "" + if err := m.core.CallPeer("tcp://"+addr.String(), from.Zone); err != nil { + m.log.Debugln("Call from multicast failed:", err) + } } } } diff --git a/src/multicast/multicast_darwin.go b/src/multicast/multicast_darwin.go index 900354c7..213bff3a 100644 --- a/src/multicast/multicast_darwin.go +++ b/src/multicast/multicast_darwin.go @@ -35,12 +35,12 @@ func (m *Multicast) multicastStarted() { if awdlGoroutineStarted { return } - m.log.Infoln("Multicast discovery will wake up AWDL if required") awdlGoroutineStarted = true for { C.StopAWDLBrowsing() - for _, intf := range m.interfaces() { + for _, intf := range m.GetInterfaces() { if intf.Name == "awdl0" { + m.log.Infoln("Multicast discovery is using AWDL discovery") C.StartAWDLBrowsing() break }