server: Add bound addresses IPC events

config.go

@@ -213,9 +213,10 @@ type config struct {
 	DropExistsAddrIndex bool `long:"dropexistsaddrindex" description:"Deletes the exists address index from the database on start up and then exits"`
 
 	// IPC options.
-	PipeRx         uint `long:"piperx" description:"File descriptor of read end pipe to enable parent -> child process communication"`
-	PipeTx         uint `long:"pipetx" description:"File descriptor of write end pipe to enable parent <- child process communication"`
-	LifetimeEvents bool `long:"lifetimeevents" description:"Send lifetime notifications over the TX pipe"`
+	PipeRx          uint `long:"piperx" description:"File descriptor of read end pipe to enable parent -> child process communication"`
+	PipeTx          uint `long:"pipetx" description:"File descriptor of write end pipe to enable parent <- child process communication"`
+	LifetimeEvents  bool `long:"lifetimeevents" description:"Send lifetime notifications over the TX pipe"`
+	BoundAddrEvents bool `long:"boundaddrevents" description:"Send notifications with the locally bound addresses of the P2P and RPC subsystems over the TX pipe"`
 
 	// Cooked options ready for use.
 	onionlookup   func(string) ([]net.IP, error)

ipc.go

@@ -205,3 +205,59 @@ func (s lifetimeEventServer) notifyShutdownEvent(action lifetimeAction) {
 		action: action,
 	}
 }
+
+// boundP2PListenAddrEvent are IPC events emitted by dcrd with the bound local
+// addresses for the P2P interface.  Multiple events of this type may be
+// generated.
+//
+// The type of this event is "p2plistenaddr" and the payload is the UTF-8
+// encoded address.
+type boundP2PListenAddrEvent string
+
+func (e boundP2PListenAddrEvent) Type() string        { return "p2plistenaddr" }
+func (e boundP2PListenAddrEvent) PayloadSize() uint32 { return uint32(len(e)) }
+func (e boundP2PListenAddrEvent) WritePayload(w io.Writer) error {
+	_, err := w.Write([]byte(e))
+	return err
+}
+
+// boundRPCListenAddrEvent are IPC events emitted by dcrd with the bound local
+// addresses for the RPC interface.  Multiple events of this type may be
+// generated.
+//
+// The type of this event is "rpclistenaddr" and the payload is the UTF-8
+// encoded address.
+type boundRPCListenAddrEvent string
+
+func (e boundRPCListenAddrEvent) Type() string        { return "rpclistenaddr" }
+func (e boundRPCListenAddrEvent) PayloadSize() uint32 { return uint32(len(e)) }
+func (e boundRPCListenAddrEvent) WritePayload(w io.Writer) error {
+	_, err := w.Write([]byte(e))
+	return err
+}
+
+// boundAddrEventServer is a server that can notify parent processes, via the
+// IPC mechanism, the local addresses to which specific subsystems are bound
+// during initialization.
+//
+// The empty value is a valid server and will not send any events if its
+// notify* methods are called.
+type boundAddrEventServer chan<- pipeMessage
+
+func newBoundAddrEventServer(outChan chan<- pipeMessage) boundAddrEventServer {
+	return boundAddrEventServer(outChan)
+}
+
+func (s boundAddrEventServer) notifyP2PAddress(addr string) {
+	if s == nil {
+		return
+	}
+	s <- boundP2PListenAddrEvent(addr)
+}
+
+func (s boundAddrEventServer) notifyRPCAddress(addr string) {
+	if s == nil {
+		return
+	}
+	s <- boundRPCListenAddrEvent(addr)
+}

server.go

@@ -3277,6 +3277,11 @@ func genCertPair(certFile, keyFile string, altDNSNames []string, tlsCurve ellipt
 // with the RPC server depending on the configuration settings for listen
 // addresses and TLS.
 func setupRPCListeners() ([]net.Listener, error) {
+	var notifyAddrServer boundAddrEventServer
+	if cfg.BoundAddrEvents {
+		notifyAddrServer = newBoundAddrEventServer(outgoingPipeMessages)
+	}
+
 	// Setup TLS if not disabled.
 	listenFunc := net.Listen
 	if !cfg.DisableRPC && !cfg.DisableTLS {
@@ -3342,6 +3347,7 @@ func setupRPCListeners() ([]net.Listener, error) {
 			continue
 		}
 		listeners = append(listeners, listener)
+		notifyAddrServer.notifyRPCAddress(listener.Addr().String())
 	}
 
 	return listeners, nil
@@ -3833,6 +3839,11 @@ func initListeners(ctx context.Context, params *chaincfg.Params, amgr *addrmgr.A
 		return nil, nil, err
 	}
 
+	var notifyAddrServer boundAddrEventServer
+	if cfg.BoundAddrEvents {
+		notifyAddrServer = newBoundAddrEventServer(outgoingPipeMessages)
+	}
+
 	listeners := make([]net.Listener, 0, len(netAddrs))
 	for _, addr := range netAddrs {
 		var listenConfig net.ListenConfig
@@ -3842,6 +3853,7 @@ func initListeners(ctx context.Context, params *chaincfg.Params, amgr *addrmgr.A
 			continue
 		}
 		listeners = append(listeners, listener)
+		notifyAddrServer.notifyP2PAddress(listener.Addr().String())
 	}
 
 	var nat *upnpNAT