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|
package p2p
import (
"fmt"
"math/rand"
"net"
"strconv"
"time"
)
const (
DialerTimeout = 180 //seconds
KeepAlivePeriod = 60 //minutes
portMappingUpdateInterval = 900 // seconds = 15 mins
upnpDiscoverAttempts = 3
)
// Dialer is not an interface in net, so we define one
// *net.Dialer conforms to this
type Dialer interface {
Dial(network, address string) (net.Conn, error)
}
type Network interface {
Start() error
Listener(net.Addr) (net.Listener, error)
Dialer(net.Addr) (Dialer, error)
NewAddr(string, int) (addr net.Addr, err error)
ParseAddr(string) (addr net.Addr, err error)
}
type NAT interface {
GetExternalAddress() (addr net.IP, err error)
AddPortMapping(protocol string, externalPort, internalPort int, description string, timeout int) (mappedExternalPort int, err error)
DeletePortMapping(protocol string, externalPort, internalPort int) (err error)
}
type TCPNetwork struct {
nat NAT
natType NATType
quit chan chan bool
ports chan string
}
type NATType int
const (
NONE = iota
UPNP
PMP
)
const (
portMappingTimeout = 1200 // 20 mins
)
func NewTCPNetwork(natType NATType) (net *TCPNetwork) {
return &TCPNetwork{
natType: natType,
ports: make(chan string),
}
}
func (self *TCPNetwork) Dialer(addr net.Addr) (Dialer, error) {
return &net.Dialer{
Timeout: DialerTimeout * time.Second,
// KeepAlive: KeepAlivePeriod * time.Minute,
LocalAddr: addr,
}, nil
}
func (self *TCPNetwork) Listener(addr net.Addr) (net.Listener, error) {
if self.natType == UPNP {
_, port, _ := net.SplitHostPort(addr.String())
if self.quit == nil {
self.quit = make(chan chan bool)
go self.updatePortMappings()
}
self.ports <- port
}
return net.Listen(addr.Network(), addr.String())
}
func (self *TCPNetwork) Start() (err error) {
switch self.natType {
case NONE:
case UPNP:
nat, uerr := upnpDiscover(upnpDiscoverAttempts)
if uerr != nil {
err = fmt.Errorf("UPNP failed: ", uerr)
} else {
self.nat = nat
}
case PMP:
err = fmt.Errorf("PMP not implemented")
default:
err = fmt.Errorf("Invalid NAT type: %v", self.natType)
}
return
}
func (self *TCPNetwork) Stop() {
q := make(chan bool)
self.quit <- q
<-q
}
func (self *TCPNetwork) addPortMapping(lport int) (err error) {
_, err = self.nat.AddPortMapping("TCP", lport, lport, "p2p listen port", portMappingTimeout)
if err != nil {
logger.Errorf("unable to add port mapping on %v: %v", lport, err)
} else {
logger.Debugf("succesfully added port mapping on %v", lport)
}
return
}
func (self *TCPNetwork) updatePortMappings() {
timer := time.NewTimer(portMappingUpdateInterval * time.Second)
lports := []int{}
out:
for {
select {
case port := <-self.ports:
int64lport, _ := strconv.ParseInt(port, 10, 16)
lport := int(int64lport)
if err := self.addPortMapping(lport); err != nil {
lports = append(lports, lport)
}
case <-timer.C:
for lport := range lports {
if err := self.addPortMapping(lport); err != nil {
}
}
case errc := <-self.quit:
errc <- true
break out
}
}
timer.Stop()
for lport := range lports {
if err := self.nat.DeletePortMapping("TCP", lport, lport); err != nil {
logger.Debugf("unable to remove port mapping on %v: %v", lport, err)
} else {
logger.Debugf("succesfully removed port mapping on %v", lport)
}
}
}
func (self *TCPNetwork) NewAddr(host string, port int) (net.Addr, error) {
ip, err := self.lookupIP(host)
if err == nil {
return &net.TCPAddr{
IP: ip,
Port: port,
}, nil
}
return nil, err
}
func (self *TCPNetwork) ParseAddr(address string) (net.Addr, error) {
host, port, err := net.SplitHostPort(address)
if err == nil {
iport, _ := strconv.Atoi(port)
addr, e := self.NewAddr(host, iport)
return addr, e
}
return nil, err
}
func (*TCPNetwork) lookupIP(host string) (ip net.IP, err error) {
if ip = net.ParseIP(host); ip != nil {
return
}
var ips []net.IP
ips, err = net.LookupIP(host)
if err != nil {
logger.Warnln(err)
return
}
if len(ips) == 0 {
err = fmt.Errorf("No IP addresses available for %v", host)
logger.Warnln(err)
return
}
if len(ips) > 1 {
// Pick a random IP address, simulating round-robin DNS.
rand.Seed(time.Now().UTC().UnixNano())
ip = ips[rand.Intn(len(ips))]
} else {
ip = ips[0]
}
return
}
|
