status-go/vendor/github.com/libp2p/go-libp2p-nat/mapping.go

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package nat
import (
"fmt"
"sync"
"time"
"github.com/jbenet/goprocess"
ma "github.com/multiformats/go-multiaddr"
manet "github.com/multiformats/go-multiaddr-net"
)
// Mapping represents a port mapping in a NAT.
type Mapping interface {
// NAT returns the NAT object this Mapping belongs to.
NAT() *NAT
// Protocol returns the protocol of this port mapping. This is either
// "tcp" or "udp" as no other protocols are likely to be NAT-supported.
Protocol() string
// InternalPort returns the internal device port. Mapping will continue to
// try to map InternalPort() to an external facing port.
InternalPort() int
// ExternalPort returns the external facing port. If the mapping is not
// established, port will be 0
ExternalPort() int
// InternalAddr returns the internal address.
InternalAddr() ma.Multiaddr
// ExternalAddr returns the external facing address. If the mapping is not
// established, addr will be nil, and and ErrNoMapping will be returned.
ExternalAddr() (addr ma.Multiaddr, err error)
// Close closes the port mapping
Close() error
}
// keeps republishing
type mapping struct {
sync.Mutex // guards all fields
nat *NAT
proto string
intport int
extport int
permanent bool
intaddr ma.Multiaddr
proc goprocess.Process
comment string
cached ma.Multiaddr
cacheTime time.Time
cacheLk sync.Mutex
}
func (m *mapping) NAT() *NAT {
m.Lock()
defer m.Unlock()
return m.nat
}
func (m *mapping) Protocol() string {
m.Lock()
defer m.Unlock()
return m.proto
}
func (m *mapping) InternalPort() int {
m.Lock()
defer m.Unlock()
return m.intport
}
func (m *mapping) ExternalPort() int {
m.Lock()
defer m.Unlock()
return m.extport
}
func (m *mapping) setExternalPort(p int) {
m.Lock()
defer m.Unlock()
m.extport = p
}
func (m *mapping) InternalAddr() ma.Multiaddr {
m.Lock()
defer m.Unlock()
return m.intaddr
}
func (m *mapping) ExternalAddr() (ma.Multiaddr, error) {
m.cacheLk.Lock()
ctime := m.cacheTime
cval := m.cached
m.cacheLk.Unlock()
if time.Since(ctime) < CacheTime {
return cval, nil
}
if m.ExternalPort() == 0 { // dont even try right now.
return nil, ErrNoMapping
}
m.nat.natmu.Lock()
ip, err := m.nat.nat.GetExternalAddress()
m.nat.natmu.Unlock()
if err != nil {
return nil, err
}
ipmaddr, err := manet.FromIP(ip)
if err != nil {
return nil, fmt.Errorf("error parsing ip")
}
// call m.ExternalPort again, as mapping may have changed under our feet. (tocttou)
extport := m.ExternalPort()
if extport == 0 {
return nil, ErrNoMapping
}
tcp, err := ma.NewMultiaddr(fmt.Sprintf("/%s/%d", m.Protocol(), extport))
if err != nil {
return nil, err
}
maddr2 := ipmaddr.Encapsulate(tcp)
m.cacheLk.Lock()
m.cached = maddr2
m.cacheTime = time.Now()
m.cacheLk.Unlock()
return maddr2, nil
}
func (m *mapping) Close() error {
return m.proc.Close()
}