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net/portmapper: add upnp port mapping

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Add in UPnP portmapping, using goupnp library in order to get the UPnP client and run the
portmapping functions. This rips out anywhere where UPnP used to be in portmapping, and has a
flow separate from PMP and PCP.

RELNOTE=portmapper now supports UPnP mappings

Fixes #682
Updates #2109

Signed-off-by: julianknodt <julianknodt@gmail.com>
This commit is contained in:
julianknodt
2021-06-22 15:29:01 -07:00
committed by Julian Knodt
parent 236eb4d04d
commit 1bb6abc604
14 changed files with 432 additions and 53 deletions
Download Patch File Download Diff File Expand all files Collapse all files

120
net/portmapper/portmapper.go
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@@ -2,8 +2,8 @@
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package portmapper is a UDP port mapping client. It currently only does
// NAT-PMP, but will likely do UPnP and perhaps PCP later.
// Package portmapper is a UDP port mapping client. It currently allows for mapping over
// NAT-PMP and UPnP, but will perhaps do PCP later.
package portmapper
import (
@@ -17,7 +17,6 @@ import (
"sync"
"time"
"go4.org/mem"
"inet.af/netaddr"
"tailscale.com/net/interfaces"
"tailscale.com/net/netns"
@@ -66,15 +65,34 @@ type Client struct {
pcpSawTime time.Time // time we last saw PCP was available
uPnPSawTime time.Time // time we last saw UPnP was available
localPort uint16
pmpMapping *pmpMapping // non-nil if we have a PMP mapping
localPort uint16
mapping mapping // non-nil if we have a mapping
}
// mapping represents a created port-mapping over some protocol. It specifies a lease duration,
// how to release the mapping, and whether the map is still valid.
//
// After a mapping is created, it should be immutable, and thus reads should be safe across
// concurrent goroutines.
type mapping interface {
// Release will attempt to unmap the established port mapping. It will block until completion,
// but can be called asynchronously. Release should be idempotent, and thus even if called
// multiple times should not cause additional side-effects.
Release(context.Context)
// goodUntil will return the lease time that the mapping is valid for.
GoodUntil() time.Time
// renewAfter returns the earliest time that the mapping should be renewed.
RenewAfter() time.Time
// externalIPPort indicates what port the mapping can be reached from on the outside.
External() netaddr.IPPort
}
// HaveMapping reports whether we have a current valid mapping.
func (c *Client) HaveMapping() bool {
c.mu.Lock()
defer c.mu.Unlock()
return c.pmpMapping != nil && c.pmpMapping.goodUntil.After(time.Now())
return c.mapping != nil && c.mapping.GoodUntil().After(time.Now())
}
// pmpMapping is an already-created PMP mapping.
@@ -94,9 +112,13 @@ func (m *pmpMapping) externalValid() bool {
return !m.external.IP().IsZero() && m.external.Port() != 0
}
// release does a best effort fire-and-forget release of the PMP mapping m.
func (m *pmpMapping) release() {
uc, err := netns.Listener().ListenPacket(context.Background(), "udp4", ":0")
func (p *pmpMapping) GoodUntil() time.Time { return p.goodUntil }
func (p *pmpMapping) RenewAfter() time.Time { return p.renewAfter }
func (p *pmpMapping) External() netaddr.IPPort { return p.external }
// Release does a best effort fire-and-forget release of the PMP mapping m.
func (m *pmpMapping) Release(ctx context.Context) {
uc, err := netns.Listener().ListenPacket(ctx, "udp4", ":0")
if err != nil {
return
}
@@ -166,7 +188,6 @@ func (c *Client) gatewayAndSelfIP() (gw, myIP netaddr.IP, ok bool) {
gw = netaddr.IP{}
myIP = netaddr.IP{}
}
c.mu.Lock()
defer c.mu.Unlock()
@@ -179,11 +200,11 @@ func (c *Client) gatewayAndSelfIP() (gw, myIP netaddr.IP, ok bool) {
}
func (c *Client) invalidateMappingsLocked(releaseOld bool) {
if c.pmpMapping != nil {
if c.mapping != nil {
if releaseOld {
c.pmpMapping.release()
c.mapping.Release(context.Background())
}
c.pmpMapping = nil
c.mapping = nil
}
c.pmpPubIP = netaddr.IP{}
c.pmpPubIPTime = time.Time{}
@@ -262,12 +283,12 @@ func (c *Client) GetCachedMappingOrStartCreatingOne() (external netaddr.IPPort,
// Do we have an existing mapping that's valid?
now := time.Now()
if m := c.pmpMapping; m != nil {
if now.Before(m.goodUntil) {
if now.After(m.renewAfter) {
if m := c.mapping; m != nil {
if now.Before(m.GoodUntil()) {
if now.After(m.RenewAfter()) {
c.maybeStartMappingLocked()
}
return m.external, true
return m.External(), true
}
}
@@ -315,9 +336,10 @@ func (c *Client) createOrGetMapping(ctx context.Context) (external netaddr.IPPor
c.mu.Lock()
localPort := c.localPort
internalAddr := netaddr.IPPortFrom(myIP, localPort)
m := &pmpMapping{
gw: gw,
internal: netaddr.IPPortFrom(myIP, localPort),
internal: internalAddr,
}
// prevPort is the port we had most previously, if any. We try
@@ -326,13 +348,13 @@ func (c *Client) createOrGetMapping(ctx context.Context) (external netaddr.IPPor
// Do we have an existing mapping that's valid?
now := time.Now()
if m := c.pmpMapping; m != nil {
if now.Before(m.renewAfter) {
if m := c.mapping; m != nil {
if now.Before(m.RenewAfter()) {
defer c.mu.Unlock()
return m.external, nil
return m.External(), nil
}
// The mapping might still be valid, so just try to renew it.
prevPort = m.external.Port()
prevPort = m.External().Port()
}
// If we just did a Probe (e.g. via netchecker) but didn't
@@ -344,6 +366,10 @@ func (c *Client) createOrGetMapping(ctx context.Context) (external netaddr.IPPor
}
if c.lastProbe.After(now.Add(-5*time.Second)) && !haveRecentPMP {
c.mu.Unlock()
// fallback to UPnP portmapping
if mapping, ok := c.getUPnPPortMapping(ctx, gw, internalAddr, prevPort); ok {
return mapping, nil
}
return netaddr.IPPort{}, NoMappingError{ErrNoPortMappingServices}
}
@@ -381,6 +407,10 @@ func (c *Client) createOrGetMapping(ctx context.Context) (external netaddr.IPPor
if ctx.Err() == context.Canceled {
return netaddr.IPPort{}, err
}
// fallback to UPnP portmapping
if mapping, ok := c.getUPnPPortMapping(ctx, gw, internalAddr, prevPort); ok {
return mapping, nil
}
return netaddr.IPPort{}, NoMappingError{ErrNoPortMappingServices}
}
srcu := srci.(*net.UDPAddr)
@@ -413,7 +443,7 @@ func (c *Client) createOrGetMapping(ctx context.Context) (external netaddr.IPPor
if m.externalValid() {
c.mu.Lock()
defer c.mu.Unlock()
c.pmpMapping = m
c.mapping = m
return m.external, nil
}
}
@@ -530,9 +560,27 @@ func (c *Client) Probe(ctx context.Context) (res ProbeResult, err error) {
defer cancel()
defer closeCloserOnContextDone(ctx, uc)()
if c.sawUPnPRecently() {
res.UPnP = true
} else {
hasUPnP := make(chan bool, 1)
defer func() {
res.UPnP = <-hasUPnP
}()
go func() {
client, err := getUPnPClient(ctx, gw)
if err == nil && client != nil {
hasUPnP <- true
c.mu.Lock()
c.uPnPSawTime = time.Now()
c.mu.Unlock()
}
close(hasUPnP)
}()
}
pcpAddr := netaddr.IPPortFrom(gw, pcpPort).UDPAddr()
pmpAddr := netaddr.IPPortFrom(gw, pmpPort).UDPAddr()
upnpAddr := netaddr.IPPortFrom(gw, upnpPort).UDPAddr()
// Don't send probes to services that we recently learned (for
// the same gw/myIP) are available. See
@@ -547,16 +595,11 @@ func (c *Client) Probe(ctx context.Context) (res ProbeResult, err error) {
} else {
uc.WriteTo(pcpAnnounceRequest(myIP), pcpAddr)
}
if c.sawUPnPRecently() {
res.UPnP = true
} else {
uc.WriteTo(uPnPPacket, upnpAddr)
}
buf := make([]byte, 1500)
pcpHeard := false // true when we get any PCP response
for {
if pcpHeard && res.PMP && res.UPnP {
if pcpHeard && res.PMP {
// Nothing more to discover.
return res, nil
}
@@ -569,13 +612,6 @@ func (c *Client) Probe(ctx context.Context) (res ProbeResult, err error) {
}
port := addr.(*net.UDPAddr).Port
switch port {
case upnpPort:
if mem.Contains(mem.B(buf[:n]), mem.S(":InternetGatewayDevice:")) {
res.UPnP = true
c.mu.Lock()
c.uPnPSawTime = time.Now()
c.mu.Unlock()
}
case pcpPort: // same as pmpPort
if pres, ok := parsePCPResponse(buf[:n]); ok {
if pres.OpCode == pcpOpReply|pcpOpAnnounce {
@@ -687,14 +723,4 @@ func parsePCPResponse(b []byte) (res pcpResponse, ok bool) {
return res, true
}
const (
upnpPort = 1900
)
var uPnPPacket = []byte("M-SEARCH * HTTP/1.1\r\n" +
"HOST: 239.255.255.250:1900\r\n" +
"ST: ssdp:all\r\n" +
"MAN: \"ssdp:discover\"\r\n" +
"MX: 2\r\n\r\n")
var pmpReqExternalAddrPacket = []byte{0, 0} // version 0, opcode 0 = "Public address request"