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