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listener.go
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listener.go
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package p2p
import (
"fmt"
"net"
"strconv"
"strings"
"time"
cmn "github.com/tendermint/tendermint/libs/common"
"github.com/tendermint/tendermint/libs/log"
"github.com/tendermint/tendermint/p2p/upnp"
)
// Listener is a network listener for stream-oriented protocols, providing
// convenient methods to get listener's internal and external addresses.
// Clients are supposed to read incoming connections from a channel, returned
// by Connections() method.
type Listener interface {
Connections() <-chan net.Conn
InternalAddress() *NetAddress
ExternalAddress() *NetAddress
ExternalAddressHost() string
String() string
Stop() error
}
// DefaultListener is a cmn.Service, running net.Listener underneath.
// Optionally, UPnP is used upon calling NewDefaultListener to resolve external
// address.
type DefaultListener struct {
cmn.BaseService
listener net.Listener
intAddr *NetAddress
extAddr *NetAddress
connections chan net.Conn
}
var _ Listener = (*DefaultListener)(nil)
const (
numBufferedConnections = 10
defaultExternalPort = 8770
tryListenSeconds = 5
)
func splitHostPort(addr string) (host string, port int) {
host, portStr, err := net.SplitHostPort(addr)
if err != nil {
panic(err)
}
port, err = strconv.Atoi(portStr)
if err != nil {
panic(err)
}
return host, port
}
// NewDefaultListener creates a new DefaultListener on lAddr, optionally trying
// to determine external address using UPnP.
func NewDefaultListener(
fullListenAddrString string,
externalAddrString string,
useUPnP bool,
logger log.Logger) Listener {
// Split protocol, address, and port.
protocol, lAddr := cmn.ProtocolAndAddress(fullListenAddrString)
lAddrIP, lAddrPort := splitHostPort(lAddr)
// Create listener
var listener net.Listener
var err error
for i := 0; i < tryListenSeconds; i++ {
listener, err = net.Listen(protocol, lAddr)
if err == nil {
break
} else if i < tryListenSeconds-1 {
time.Sleep(time.Second * 1)
}
}
if err != nil {
panic(err)
}
// Actual listener local IP & port
listenerIP, listenerPort := splitHostPort(listener.Addr().String())
logger.Info("Local listener", "ip", listenerIP, "port", listenerPort)
// Determine internal address...
var intAddr *NetAddress
intAddr, err = NewNetAddressStringWithOptionalID(lAddr)
if err != nil {
panic(err)
}
inAddrAny := lAddrIP == "" || lAddrIP == "0.0.0.0"
// Determine external address.
var extAddr *NetAddress
if externalAddrString != "" {
var err error
extAddr, err = NewNetAddressStringWithOptionalID(externalAddrString)
if err != nil {
panic(fmt.Sprintf("Error in ExternalAddress: %v", err))
}
}
// If the lAddrIP is INADDR_ANY, try UPnP.
if extAddr == nil && useUPnP && inAddrAny {
extAddr = getUPNPExternalAddress(lAddrPort, listenerPort, logger)
}
// Otherwise just use the local address.
if extAddr == nil {
defaultToIPv4 := inAddrAny
extAddr = getNaiveExternalAddress(defaultToIPv4, listenerPort, false, logger)
}
if extAddr == nil {
panic("Could not determine external address!")
}
dl := &DefaultListener{
listener: listener,
intAddr: intAddr,
extAddr: extAddr,
connections: make(chan net.Conn, numBufferedConnections),
}
dl.BaseService = *cmn.NewBaseService(logger, "DefaultListener", dl)
err = dl.Start() // Started upon construction
if err != nil {
logger.Error("Error starting base service", "err", err)
}
return dl
}
// OnStart implements cmn.Service by spinning a goroutine, listening for new
// connections.
func (l *DefaultListener) OnStart() error {
if err := l.BaseService.OnStart(); err != nil {
return err
}
go l.listenRoutine()
return nil
}
// OnStop implements cmn.Service by closing the listener.
func (l *DefaultListener) OnStop() {
l.BaseService.OnStop()
l.listener.Close() // nolint: errcheck
}
// Accept connections and pass on the channel
func (l *DefaultListener) listenRoutine() {
for {
conn, err := l.listener.Accept()
if !l.IsRunning() {
break // Go to cleanup
}
// listener wasn't stopped,
// yet we encountered an error.
if err != nil {
panic(err)
}
l.connections <- conn
}
// Cleanup
close(l.connections)
for range l.connections {
// Drain
}
}
// Connections returns a channel of inbound connections.
// It gets closed when the listener closes.
func (l *DefaultListener) Connections() <-chan net.Conn {
return l.connections
}
// InternalAddress returns the internal NetAddress (address used for
// listening).
func (l *DefaultListener) InternalAddress() *NetAddress {
return l.intAddr
}
// ExternalAddress returns the external NetAddress (publicly available,
// determined using either UPnP or local resolver).
func (l *DefaultListener) ExternalAddress() *NetAddress {
return l.extAddr
}
// ExternalAddressHost returns the external NetAddress IP string. If an IP is
// IPv6, it's wrapped in brackets ("[2001:db8:1f70::999:de8:7648:6e8]").
func (l *DefaultListener) ExternalAddressHost() string {
ip := l.ExternalAddress().IP
if isIpv6(ip) {
// Means it's ipv6, so format it with brackets
return "[" + ip.String() + "]"
}
return ip.String()
}
func (l *DefaultListener) String() string {
return fmt.Sprintf("Listener(@%v)", l.extAddr)
}
/* external address helpers */
// UPNP external address discovery & port mapping
func getUPNPExternalAddress(externalPort, internalPort int, logger log.Logger) *NetAddress {
logger.Info("Getting UPNP external address")
nat, err := upnp.Discover()
if err != nil {
logger.Info("Could not perform UPNP discover", "err", err)
return nil
}
ext, err := nat.GetExternalAddress()
if err != nil {
logger.Info("Could not get UPNP external address", "err", err)
return nil
}
// UPnP can't seem to get the external port, so let's just be explicit.
if externalPort == 0 {
externalPort = defaultExternalPort
}
externalPort, err = nat.AddPortMapping("tcp", externalPort, internalPort, "tendermint", 0)
if err != nil {
logger.Info("Could not add UPNP port mapping", "err", err)
return nil
}
logger.Info("Got UPNP external address", "address", ext)
return NewNetAddressIPPort(ext, uint16(externalPort))
}
func isIpv6(ip net.IP) bool {
v4 := ip.To4()
if v4 != nil {
return false
}
ipString := ip.String()
// Extra check just to be sure it's IPv6
return (strings.Contains(ipString, ":") && !strings.Contains(ipString, "."))
}
// TODO: use syscalls: see issue #712
func getNaiveExternalAddress(defaultToIPv4 bool, port int, settleForLocal bool, logger log.Logger) *NetAddress {
addrs, err := net.InterfaceAddrs()
if err != nil {
panic(cmn.Fmt("Could not fetch interface addresses: %v", err))
}
for _, a := range addrs {
ipnet, ok := a.(*net.IPNet)
if !ok {
continue
}
if defaultToIPv4 || !isIpv6(ipnet.IP) {
v4 := ipnet.IP.To4()
if v4 == nil || (!settleForLocal && v4[0] == 127) {
// loopback
continue
}
} else if !settleForLocal && ipnet.IP.IsLoopback() {
// IPv6, check for loopback
continue
}
return NewNetAddressIPPort(ipnet.IP, uint16(port))
}
// try again, but settle for local
logger.Info("Node may not be connected to internet. Settling for local address")
return getNaiveExternalAddress(defaultToIPv4, port, true, logger)
}