// Copyright (C) 2015 The Syncthing Authors. // // This Source Code Form is subject to the terms of the Mozilla Public // License, v. 2.0. If a copy of the MPL was not distributed with this file, // You can obtain one at https://mozilla.org/MPL/2.0/. package nat import ( "fmt" "net" "time" "github.com/syncthing/syncthing/lib/sync" ) type MappingChangeSubscriber func(*Mapping, []Address, []Address) type Mapping struct { protocol Protocol address Address extAddresses map[string]Address // NAT ID -> Address expires time.Time subscribers []MappingChangeSubscriber mut sync.RWMutex } func (m *Mapping) setAddress(id string, address Address) { m.mut.Lock() if existing, ok := m.extAddresses[id]; !ok || !existing.Equal(address) { l.Infof("New NAT port mapping: external %s address %s to local address %s.", m.protocol, address, m.address) m.extAddresses[id] = address } m.mut.Unlock() } func (m *Mapping) removeAddress(id string) { m.mut.Lock() addr, ok := m.extAddresses[id] if ok { l.Infof("Removing NAT port mapping: external %s address %s, NAT %s is no longer available.", m.protocol, addr, id) delete(m.extAddresses, id) } m.mut.Unlock() } func (m *Mapping) clearAddresses() { m.mut.Lock() var removed []Address for id, addr := range m.extAddresses { l.Debugf("Clearing mapping %s: ID: %s Address: %s", m, id, addr) removed = append(removed, addr) delete(m.extAddresses, id) } m.expires = time.Time{} m.mut.Unlock() if len(removed) > 0 { m.notify(nil, removed) } } func (m *Mapping) notify(added, removed []Address) { m.mut.RLock() for _, subscriber := range m.subscribers { subscriber(m, added, removed) } m.mut.RUnlock() } func (m *Mapping) addressMap() map[string]Address { m.mut.RLock() addrMap := m.extAddresses m.mut.RUnlock() return addrMap } func (m *Mapping) Protocol() Protocol { return m.protocol } func (m *Mapping) Address() Address { return m.address } func (m *Mapping) ExternalAddresses() []Address { m.mut.RLock() addrs := make([]Address, 0, len(m.extAddresses)) for _, addr := range m.extAddresses { addrs = append(addrs, addr) } m.mut.RUnlock() return addrs } func (m *Mapping) OnChanged(subscribed MappingChangeSubscriber) { m.mut.Lock() m.subscribers = append(m.subscribers, subscribed) m.mut.Unlock() } func (m *Mapping) String() string { return fmt.Sprintf("%s %s", m.protocol, m.address) } func (m *Mapping) GoString() string { return m.String() } // Checks if the mappings local IP address matches the IP address of the gateway // For example, if we are explicitly listening on 192.168.0.12, there is no // point trying to acquire a mapping on a gateway to which the local IP is // 10.0.0.1. Fallback to true if any of the IPs is not there. func (m *Mapping) validGateway(ip net.IP) bool { if m.address.IP == nil || ip == nil || m.address.IP.IsUnspecified() || ip.IsUnspecified() { return true } return m.address.IP.Equal(ip) } // Address is essentially net.TCPAddr yet is more general, and has a few helper // methods which reduce boilerplate code. type Address struct { IP net.IP Port int } func (a Address) Equal(b Address) bool { return a.Port == b.Port && a.IP.Equal(b.IP) } func (a Address) String() string { var ipStr string if a.IP == nil { ipStr = net.IPv4zero.String() } else { ipStr = a.IP.String() } return net.JoinHostPort(ipStr, fmt.Sprintf("%d", a.Port)) } func (a Address) GoString() string { return a.String() }