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package p2p
import (
"fmt"
"net"
"strconv"
"sync/atomic"
. "github.com/tendermint/tendermint2/common"
"github.com/tendermint/tendermint2/p2p/upnp"
)
type Listener interface {
Connections() <-chan net.Conn
ExternalAddress() *NetAddress
Stop()
}
// Implements Listener
type DefaultListener struct {
listener net.Listener
extAddr *NetAddress
connections chan net.Conn
stopped uint32
}
const (
numBufferedConnections = 10
defaultExternalPort = 8770
)
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
}
func NewDefaultListener(protocol string, lAddr string, requireUPNPHairpin bool) Listener {
// Local listen IP & port
lAddrIP, lAddrPort := splitHostPort(lAddr)
// Create listener
listener, err := net.Listen(protocol, lAddr)
if err != nil {
panic(err)
}
// Actual listener local IP & port
listenerIP, listenerPort := splitHostPort(listener.Addr().String())
log.Debug("Local listener", "ip", listenerIP, "port", listenerPort)
// Determine external address...
var extAddr *NetAddress
// If the lAddrIP is INADDR_ANY, try UPnP
if lAddrIP == "" || lAddrIP == "0.0.0.0" {
if requireUPNPHairpin {
upnpCapabilities, err := upnp.Probe()
if err != nil {
log.Warn("Failed to probe UPNP", "error", err)
goto SKIP_UPNP
}
if !upnpCapabilities.Hairpin {
goto SKIP_UPNP
}
}
extAddr = getUPNPExternalAddress(lAddrPort, listenerPort)
}
SKIP_UPNP:
// Otherwise just use the local address...
if extAddr == nil {
extAddr = getNaiveExternalAddress(listenerPort)
}
if extAddr == nil {
panic("Could not determine external address!")
}
dl := &DefaultListener{
listener: listener,
extAddr: extAddr,
connections: make(chan net.Conn, numBufferedConnections),
}
go dl.listenRoutine()
return dl
}
// TODO: prevent abuse, esp a bunch of connections coming from the same IP range.
func (l *DefaultListener) listenRoutine() {
for {
conn, err := l.listener.Accept()
if atomic.LoadUint32(&l.stopped) == 1 {
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
}
}
// A channel of inbound connections.
// It gets closed when the listener closes.
func (l *DefaultListener) Connections() <-chan net.Conn {
return l.connections
}
func (l *DefaultListener) ExternalAddress() *NetAddress {
return l.extAddr
}
func (l *DefaultListener) Stop() {
if atomic.CompareAndSwapUint32(&l.stopped, 0, 1) {
l.listener.Close()
}
}
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) *NetAddress {
log.Debug("Getting UPNP external address")
nat, err := upnp.Discover()
if err != nil {
log.Debug("Could not get UPNP extrernal address", "error", err)
return nil
}
ext, err := nat.GetExternalAddress()
if err != nil {
log.Debug("Could not get UPNP external address", "error", 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 {
log.Debug("Could not get UPNP external address", "error", err)
return nil
}
log.Debug("Got UPNP external address", "address", ext)
return NewNetAddressIPPort(ext, uint16(externalPort))
}
// TODO: use syscalls: http://pastebin.com/9exZG4rh
func getNaiveExternalAddress(port int) *NetAddress {
addrs, err := net.InterfaceAddrs()
if err != nil {
panic(Fmt("Could not fetch interface addresses: %v", err))
}
for _, a := range addrs {
ipnet, ok := a.(*net.IPNet)
if !ok {
continue
}
v4 := ipnet.IP.To4()
if v4 == nil || v4[0] == 127 {
continue
} // loopback
return NewNetAddressIPPort(ipnet.IP, uint16(port))
}
return nil
}