mirror of https://github.com/tailscale/tailscale/
all: make client use server-provided DERP map, add DERP region support
Instead of hard-coding the DERP map (except for cmd/tailscale netcheck for now), get it from the control server at runtime. And make the DERP map support multiple nodes per region with clients picking the first one that's available. (The server will balance the order presented to clients for load balancing) This deletes the stunner package, merging it into the netcheck package instead, to minimize all the config hooks that would've been required. Also fix some test flakes & races. Fixes #387 (Don't hard-code the DERP map) Updates #388 (Add DERP region support) Fixes #399 (wgengine: flaky tests) Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>pull/404/head
Brad Fitzpatrick
4 years ago
committed by
Brad Fitzpatrick
parent
e8b3a5e7a1
commit
e6b84f2159
File diff suppressed because it is too large
Load Diff
@ -1,310 +0,0 @@
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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package stunner
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import (
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"context"
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"errors"
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"fmt"
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"math/rand"
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"net"
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"strconv"
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"strings"
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"sync"
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"time"
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"tailscale.com/net/dnscache"
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"tailscale.com/stun"
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"tailscale.com/types/structs"
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)
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// Stunner sends a STUN request to several servers and handles a response.
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//
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// It is designed to used on a connection owned by other code and so does
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// not directly reference a net.Conn of any sort. Instead, the user should
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// provide Send function to send packets, and call Receive when a new
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// STUN response is received.
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//
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// In response, a Stunner will call Endpoint with any endpoints determined
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// for the connection. (An endpoint may be reported multiple times if
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// multiple servers are provided.)
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type Stunner struct {
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// Send sends a packet.
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// It will typically be a PacketConn.WriteTo method value.
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Send func([]byte, net.Addr) (int, error) // sends a packet
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// Endpoint is called whenever a STUN response is received.
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// The server is the STUN server that replied, endpoint is the ip:port
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// from the STUN response, and d is the duration that the STUN request
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// took on the wire (not including DNS lookup time.
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Endpoint func(server, endpoint string, d time.Duration)
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// onPacket is the internal version of Endpoint that does de-dup.
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// It's set by Run.
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onPacket func(server, endpoint string, d time.Duration)
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Servers []string // STUN servers to contact
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// DNSCache optionally specifies a DNSCache to use.
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// If nil, a DNS cache is not used.
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DNSCache *dnscache.Resolver
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// Logf optionally specifies a log function. If nil, logging is disabled.
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Logf func(format string, args ...interface{})
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// OnlyIPv6 controls whether IPv6 is exclusively used.
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// If false, only IPv4 is used. There is currently no mixed mode.
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OnlyIPv6 bool
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// MaxTries optionally provides a mapping from server name to the maximum
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// number of tries that should be made for a given server.
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// If nil or a server is not present in the map, the default is 1.
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// Values less than 1 are ignored.
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MaxTries map[string]int
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mu sync.Mutex
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inFlight map[stun.TxID]request
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}
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func (s *Stunner) addTX(tx stun.TxID, server string) {
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s.mu.Lock()
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defer s.mu.Unlock()
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if _, dup := s.inFlight[tx]; dup {
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panic("unexpected duplicate STUN TransactionID")
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}
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s.inFlight[tx] = request{sent: time.Now(), server: server}
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}
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func (s *Stunner) removeTX(tx stun.TxID) (request, bool) {
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s.mu.Lock()
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defer s.mu.Unlock()
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if s.inFlight == nil {
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return request{}, false
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}
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r, ok := s.inFlight[tx]
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if ok {
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delete(s.inFlight, tx)
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} else {
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s.logf("stunner: got STUN packet for unknown TxID %x", tx)
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}
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return r, ok
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}
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type request struct {
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_ structs.Incomparable
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sent time.Time
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server string
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}
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func (s *Stunner) logf(format string, args ...interface{}) {
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if s.Logf != nil {
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s.Logf(format, args...)
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}
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}
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// Receive delivers a STUN packet to the stunner.
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func (s *Stunner) Receive(p []byte, fromAddr *net.UDPAddr) {
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if !stun.Is(p) {
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s.logf("[unexpected] stunner: received non-STUN packet")
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return
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}
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now := time.Now()
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tx, addr, port, err := stun.ParseResponse(p)
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if err != nil {
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if _, err := stun.ParseBindingRequest(p); err == nil {
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// This was probably our own netcheck hairpin
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// check probe coming in late. Ignore.
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return
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}
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s.logf("stunner: received unexpected STUN message response from %v: %v", fromAddr, err)
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return
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}
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r, ok := s.removeTX(tx)
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if !ok {
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return
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}
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d := now.Sub(r.sent)
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host := net.JoinHostPort(net.IP(addr).String(), fmt.Sprint(port))
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s.onPacket(r.server, host, d)
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}
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func (s *Stunner) resolver() *net.Resolver {
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return net.DefaultResolver
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}
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// cleanUpPostRun zeros out some fields, mostly for debugging (so
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// things crash or race+fail if there's a sender still running.)
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func (s *Stunner) cleanUpPostRun() {
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s.mu.Lock()
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s.inFlight = nil
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s.mu.Unlock()
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}
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// Run starts a Stunner and blocks until all servers either respond
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// or are tried multiple times and timeout.
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// It can not be called concurrently with itself.
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func (s *Stunner) Run(ctx context.Context) error {
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for _, server := range s.Servers {
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if _, _, err := net.SplitHostPort(server); err != nil {
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return fmt.Errorf("Stunner.Run: invalid server %q (in Server list %q)", server, s.Servers)
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}
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}
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if len(s.Servers) == 0 {
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return errors.New("stunner: no Servers")
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}
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s.inFlight = make(map[stun.TxID]request)
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defer s.cleanUpPostRun()
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ctx, cancel := context.WithCancel(ctx)
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defer cancel()
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type sender struct {
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ctx context.Context
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cancel context.CancelFunc
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}
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var (
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needMu sync.Mutex
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need = make(map[string]sender) // keyed by server; deleted when done
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allDone = make(chan struct{}) // closed when need is empty
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)
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s.onPacket = func(server, endpoint string, d time.Duration) {
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needMu.Lock()
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defer needMu.Unlock()
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sender, ok := need[server]
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if !ok {
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return
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}
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sender.cancel()
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delete(need, server)
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s.Endpoint(server, endpoint, d)
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if len(need) == 0 {
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close(allDone)
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}
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}
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var wg sync.WaitGroup
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for _, server := range s.Servers {
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ctx, cancel := context.WithCancel(ctx)
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defer cancel()
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need[server] = sender{ctx, cancel}
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}
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needMu.Lock()
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for server, sender := range need {
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wg.Add(1)
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server, ctx := server, sender.ctx
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go func() {
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defer wg.Done()
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s.sendPackets(ctx, server)
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}()
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}
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needMu.Unlock()
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var err error
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select {
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case <-ctx.Done():
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err = ctx.Err()
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case <-allDone:
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cancel()
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}
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wg.Wait()
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var missing []string
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needMu.Lock()
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for server := range need {
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missing = append(missing, server)
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}
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needMu.Unlock()
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if len(missing) == 0 || err == nil {
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return nil
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}
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return fmt.Errorf("got STUN error: %w; missing replies from: %v", err, strings.Join(missing, ", "))
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}
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func (s *Stunner) serverAddr(ctx context.Context, server string) (*net.UDPAddr, error) {
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hostStr, portStr, err := net.SplitHostPort(server)
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if err != nil {
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return nil, err
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}
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addrPort, err := strconv.Atoi(portStr)
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if err != nil {
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return nil, fmt.Errorf("port: %v", err)
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}
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if addrPort == 0 {
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addrPort = 3478
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}
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addr := &net.UDPAddr{Port: addrPort}
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var ipAddrs []net.IPAddr
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if s.DNSCache != nil {
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ip, err := s.DNSCache.LookupIP(ctx, hostStr)
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if err != nil {
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return nil, err
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}
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ipAddrs = []net.IPAddr{{IP: ip}}
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} else {
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ipAddrs, err = s.resolver().LookupIPAddr(ctx, hostStr)
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if err != nil {
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return nil, fmt.Errorf("lookup ip addr (%q): %v", hostStr, err)
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}
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}
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for _, ipAddr := range ipAddrs {
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ip4 := ipAddr.IP.To4()
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if ip4 != nil {
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if s.OnlyIPv6 {
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continue
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}
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addr.IP = ip4
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break
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} else if s.OnlyIPv6 {
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addr.IP = ipAddr.IP
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addr.Zone = ipAddr.Zone
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}
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}
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if addr.IP == nil {
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if s.OnlyIPv6 {
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return nil, fmt.Errorf("cannot resolve any ipv6 addresses for %s, got: %v", server, ipAddrs)
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}
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return nil, fmt.Errorf("cannot resolve any ipv4 addresses for %s, got: %v", server, ipAddrs)
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}
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return addr, nil
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}
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// maxTriesForServer returns the maximum number of STUN queries that
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// will be sent to server (for one call to Run). The default is 1.
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func (s *Stunner) maxTriesForServer(server string) int {
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if v, ok := s.MaxTries[server]; ok && v > 0 {
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return v
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}
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return 1
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}
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func (s *Stunner) sendPackets(ctx context.Context, server string) error {
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addr, err := s.serverAddr(ctx, server)
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if err != nil {
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return err
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}
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maxTries := s.maxTriesForServer(server)
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for i := 0; i < maxTries; i++ {
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txID := stun.NewTxID()
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req := stun.Request(txID)
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s.addTX(txID, server)
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_, err = s.Send(req, addr)
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if err != nil {
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return fmt.Errorf("send: %v", err)
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}
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select {
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case <-ctx.Done():
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// Ignore error. The caller deals with handling contexts.
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// We only use it to dermine when to stop spraying STUN packets.
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return nil
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case <-time.After(time.Millisecond * time.Duration(50+rand.Intn(200))):
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}
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}
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return nil
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}
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@ -1,154 +0,0 @@
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// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package stunner
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import (
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"context"
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"errors"
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"fmt"
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"net"
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"sort"
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"testing"
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"time"
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"gortc.io/stun"
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)
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func TestStun(t *testing.T) {
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conn1, err := net.ListenPacket("udp4", "127.0.0.1:0")
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if err != nil {
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t.Fatal(err)
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}
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defer conn1.Close()
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conn2, err := net.ListenPacket("udp4", "127.0.0.1:0")
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if err != nil {
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t.Fatal(err)
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}
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defer conn2.Close()
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stunServers := []string{
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conn1.LocalAddr().String(), conn2.LocalAddr().String(),
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}
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epCh := make(chan string, 16)
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localConn, err := net.ListenPacket("udp4", "127.0.0.1:0")
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if err != nil {
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t.Fatal(err)
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}
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s := &Stunner{
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Send: localConn.WriteTo,
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Endpoint: func(server, ep string, d time.Duration) { epCh <- ep },
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Servers: stunServers,
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MaxTries: map[string]int{
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stunServers[0]: 2,
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stunServers[1]: 2,
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},
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}
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stun1Err := make(chan error)
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go func() {
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stun1Err <- startSTUN(conn1, s.Receive)
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}()
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stun2Err := make(chan error)
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go func() {
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stun2Err <- startSTUNDrop1(conn2, s.Receive)
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}()
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errCh := make(chan error)
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go func() {
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errCh <- s.Run(context.Background())
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}()
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var eps []string
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select {
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case ep := <-epCh:
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eps = append(eps, ep)
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case <-time.After(100 * time.Millisecond):
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t.Fatal("missing first endpoint response")
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}
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select {
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case ep := <-epCh:
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eps = append(eps, ep)
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case <-time.After(500 * time.Millisecond):
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t.Fatal("missing second endpoint response")
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}
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sort.Strings(eps)
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if want := "1.2.3.4:1234"; eps[0] != want {
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t.Errorf("eps[0]=%q, want %q", eps[0], want)
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}
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if want := "4.5.6.7:4567"; eps[1] != want {
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t.Errorf("eps[1]=%q, want %q", eps[1], want)
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}
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if err := <-errCh; err != nil {
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t.Fatal(err)
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}
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}
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func startSTUNDrop1(conn net.PacketConn, writeTo func([]byte, *net.UDPAddr)) error {
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if _, _, err := conn.ReadFrom(make([]byte, 1024)); err != nil {
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return fmt.Errorf("first stun server read failed: %v", err)
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}
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req := new(stun.Message)
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res := new(stun.Message)
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p := make([]byte, 1024)
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n, addr, err := conn.ReadFrom(p)
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if err != nil {
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return err
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}
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p = p[:n]
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if !stun.IsMessage(p) {
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return errors.New("not a STUN message")
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}
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if _, err := req.Write(p); err != nil {
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return err
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}
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mappedAddr := &stun.XORMappedAddress{
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IP: net.ParseIP("1.2.3.4"),
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Port: 1234,
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}
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software := stun.NewSoftware("endpointer")
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err = res.Build(req, stun.BindingSuccess, software, mappedAddr, stun.Fingerprint)
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if err != nil {
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return err
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}
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writeTo(res.Raw, addr.(*net.UDPAddr))
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return nil
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}
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func startSTUN(conn net.PacketConn, writeTo func([]byte, *net.UDPAddr)) error {
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req := new(stun.Message)
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res := new(stun.Message)
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p := make([]byte, 1024)
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n, addr, err := conn.ReadFrom(p)
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if err != nil {
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return err
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}
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p = p[:n]
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if !stun.IsMessage(p) {
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return errors.New("not a STUN message")
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}
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if _, err := req.Write(p); err != nil {
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return err
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}
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mappedAddr := &stun.XORMappedAddress{
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IP: net.ParseIP("4.5.6.7"),
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Port: 4567,
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}
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software := stun.NewSoftware("endpointer")
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err = res.Build(req, stun.BindingSuccess, software, mappedAddr, stun.Fingerprint)
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if err != nil {
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return err
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}
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writeTo(res.Raw, addr.(*net.UDPAddr))
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return nil
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}
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||||
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||||
// TODO: test retry timeout (overwrite the retryDurations)
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||||
// TODO: test canceling context passed to Run
|
||||
// TODO: test sending bad packets
|
||||
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Reference in New Issue