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Add gathering generation extension to candidates #874

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98 changes: 80 additions & 18 deletions agent.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -11,6 +11,7 @@ import (
"math"
"net"
"net/netip"
"strconv"
"strings"
"sync"
"sync/atomic"
Expand Down Expand Up @@ -58,8 +59,10 @@ type Agent struct {
tieBreaker uint64
lite bool

connectionState ConnectionState
gatheringState GatheringState
connectionState ConnectionState
gatheringState GatheringState
gatherGeneration uint64
gatherEndSent bool

mDNSMode MulticastDNSMode
mDNSName string
Expand Down Expand Up @@ -1052,28 +1055,39 @@ func (a *Agent) addRemoteCandidate(cand Candidate) { //nolint:cyclop
a.requestConnectivityCheck()
}

func (a *Agent) addCandidate(ctx context.Context, cand Candidate, candidateConn net.PacketConn) error {
func (a *Agent) addCandidate(ctx context.Context, cand Candidate, candidateConn net.PacketConn, gen uint64) error {
if err := ctx.Err(); err != nil {
return err
}

cleanupCandidate := func(reason string) {
if err := cand.close(); err != nil {
a.log.Warnf("Failed to close %s candidate: %v", reason, err)
}
if err := candidateConn.Close(); err != nil {
a.log.Warnf("Failed to close %s candidate connection: %v", reason, err)
}
}

return a.loop.Run(ctx, func(context.Context) {
if a.gatherGeneration != gen {
a.log.Debugf("Ignoring candidate from different gather generation (a: %d c: %d)", a.gatherGeneration, gen)
cleanupCandidate("old")

return
}

set := a.localCandidates[cand.NetworkType()]
for _, candidate := range set {
if candidate.Equal(cand) {
a.log.Debugf("Ignore duplicate candidate: %s", cand)
if err := cand.close(); err != nil {
a.log.Warnf("Failed to close duplicate candidate: %v", err)
}
if err := candidateConn.Close(); err != nil {
a.log.Warnf("Failed to close duplicate candidate connection: %v", err)
}
cleanupCandidate("duplicate")

return
}
}

a.setCandidateExtensions(cand)
a.setCandidateExtensions(cand, gen)
cand.start(a, candidateConn, a.startedCh)

set = append(set, cand)
Expand All @@ -1093,14 +1107,22 @@ func (a *Agent) addCandidate(ctx context.Context, cand Candidate, candidateConn
})
}

func (a *Agent) setCandidateExtensions(cand Candidate) {
func (a *Agent) setCandidateExtensions(cand Candidate, candidateGeneration uint64) {
err := cand.AddExtension(CandidateExtension{
Key: "ufrag",
Value: a.localUfrag,
})
if err != nil {
a.log.Errorf("Failed to add ufrag extension to candidate: %v", err)
}

err = cand.AddExtension(CandidateExtension{
Key: "generation",
Value: strconv.FormatUint(candidateGeneration, 10),
})
if err != nil {
a.log.Errorf("Failed to add generation extension to candidate: %v", err)
}
}

// GetRemoteCandidates returns the remote candidates.
Expand Down Expand Up @@ -1633,18 +1655,22 @@ func (a *Agent) Restart(ufrag, pwd string) error { //nolint:cyclop
}

var err error
var shouldNotifyGatherEnd bool
if runErr := a.loop.Run(a.loop, func(_ context.Context) {
if a.gatheringState == GatheringStateGathering {
a.gatherCandidateCancel()
}
if a.gatheringState != GatheringStateNew {
shouldNotifyGatherEnd = a.setGatheringStateLocked(GatheringStateComplete, a.gatherGeneration)
}
a.bumpGatheringGenerationLocked()

// Clear all agent needed to take back to fresh state
a.removeUfragFromMux()
a.localUfrag = ufrag
a.localPwd = pwd
a.remoteUfrag = ""
a.remotePwd = ""
a.gatheringState = GatheringStateNew
a.checklist = make([]*CandidatePair, 0)
a.pairsByID = make(map[uint64]*CandidatePair)
a.pendingBindingRequests = make([]bindingRequest, 0)
Expand All @@ -1661,27 +1687,63 @@ func (a *Agent) Restart(ufrag, pwd string) error { //nolint:cyclop
return runErr
}

if shouldNotifyGatherEnd {
a.candidateNotifier.EnqueueCandidate(nil)
}

return err
}

func (a *Agent) setGatheringState(newState GatheringState) error {
func (a *Agent) setGatheringState(newState GatheringState, generation uint64) error {
var shouldNotifyGatherEnd bool
done := make(chan struct{})
if err := a.loop.Run(a.loop, func(context.Context) {
if a.gatheringState != newState && newState == GatheringStateComplete {
a.candidateNotifier.EnqueueCandidate(nil)
}

a.gatheringState = newState
shouldNotifyGatherEnd = a.setGatheringStateLocked(newState, generation)
close(done)
}); err != nil {
return err
}

<-done

if shouldNotifyGatherEnd {
a.candidateNotifier.EnqueueCandidate(nil)
}

return nil
}

// setGatheringStateLocked updates the gathering state and returns true if
// the caller should send an end-of-candidates notification (nil candidate)
// via a.candidateNotifier.EnqueueCandidate(nil). The notification is deferred
// to the caller so that it happens outside the agent loop, avoiding nested
// lock acquisition between the loop and the notifier.
func (a *Agent) setGatheringStateLocked(newState GatheringState, generation uint64) bool {
if generation != a.gatherGeneration {
return false
}

if a.gatheringState == newState {
return false
}

a.gatheringState = newState

if newState == GatheringStateComplete && !a.gatherEndSent {
a.gatherEndSent = true

return true
}

return false
}

func (a *Agent) bumpGatheringGenerationLocked() {
a.gatherGeneration++
a.gatherEndSent = false
a.gatheringState = GatheringStateNew
}

func (a *Agent) needsToCheckPriorityOnNominated() bool {
return !a.lite || a.enableUseCandidateCheckPriority
}
Expand Down
89 changes: 80 additions & 9 deletions agent_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1385,9 +1385,7 @@ func TestAgentRestart(t *testing.T) {

t.Run("Restart Both Sides", func(t *testing.T) {
// Get all addresses of candidates concatenated
generateCandidateAddressStrings := func(candidates []Candidate, err error) (out string) {
require.NoError(t, err)

generateCandidateAddressStrings := func(candidates []Candidate) (out string) {
for _, c := range candidates {
out += c.Address() + ":"
out += strconv.Itoa(c.Port())
Expand All @@ -1396,14 +1394,31 @@ func TestAgentRestart(t *testing.T) {
return
}

candidateHasGeneration := func(generation uint64, candidate Candidate) {
genString := strconv.FormatUint(generation, 10)
ext, ok := candidate.GetExtension("generation")

require.True(t, ok)
require.Equal(t, genString, ext.Value)
}

// Store the original candidates, confirm that after we reconnect we have new pairs
connA, connB := pipe(t, &AgentConfig{
DisconnectedTimeout: &oneSecond,
FailedTimeout: &oneSecond,
})
defer closePipe(t, connA, connB)
connAFirstCandidates := generateCandidateAddressStrings(connA.agent.GetLocalCandidates())
connBFirstCandidates := generateCandidateAddressStrings(connB.agent.GetLocalCandidates())

aFirstGeneration := connA.agent.gatherGeneration
bFirstGeneration := connB.agent.gatherGeneration

connAFirstCandidates, err := connA.agent.GetLocalCandidates()
require.NoError(t, err)
connBFirstCandidates, err := connB.agent.GetLocalCandidates()
require.NoError(t, err)

candidateHasGeneration(aFirstGeneration, connAFirstCandidates[0])
candidateHasGeneration(bFirstGeneration, connBFirstCandidates[0])

aNotifier, aConnected := onConnected()
require.NoError(t, connA.agent.OnConnectionStateChange(aNotifier))
Expand All @@ -1415,6 +1430,10 @@ func TestAgentRestart(t *testing.T) {
require.NoError(t, connA.agent.Restart("", ""))
require.NoError(t, connB.agent.Restart("", ""))

// Generation should change after Restart call
require.NotEqual(t, aFirstGeneration, connA.agent.gatherGeneration)
require.NotEqual(t, bFirstGeneration, connB.agent.gatherGeneration)

// Exchange Candidates and Credentials
ufrag, pwd, err := connB.agent.GetLocalUserCredentials()
require.NoError(t, err)
Expand All @@ -1430,9 +1449,21 @@ func TestAgentRestart(t *testing.T) {
<-aConnected
<-bConnected

connASecondCandidates, err := connA.agent.GetLocalCandidates()
require.NoError(t, err)
connBSecondCandidates, err := connB.agent.GetLocalCandidates()
require.NoError(t, err)

candidateHasGeneration(connA.agent.gatherGeneration, connASecondCandidates[0])
candidateHasGeneration(connB.agent.gatherGeneration, connASecondCandidates[0])

// Assert that we have new candidates each time
require.NotEqual(t, connAFirstCandidates, generateCandidateAddressStrings(connA.agent.GetLocalCandidates()))
require.NotEqual(t, connBFirstCandidates, generateCandidateAddressStrings(connB.agent.GetLocalCandidates()))
aFirstCandidatesString := generateCandidateAddressStrings(connAFirstCandidates)
aSecondCandidatesString := generateCandidateAddressStrings(connASecondCandidates)
bFirstCandidatesString := generateCandidateAddressStrings(connBFirstCandidates)
bSecondCandidatesString := generateCandidateAddressStrings(connBSecondCandidates)
require.NotEqual(t, aFirstCandidatesString, aSecondCandidatesString)
require.NotEqual(t, bFirstCandidatesString, bSecondCandidatesString)
})
}

Expand Down Expand Up @@ -1511,7 +1542,7 @@ func TestGetLocalCandidates(t *testing.T) {

expectedCandidates = append(expectedCandidates, cand)

err = agent.addCandidate(context.Background(), cand, dummyConn)
err = agent.addCandidate(context.Background(), cand, dummyConn, agent.gatherGeneration)
require.NoError(t, err)
}

Expand Down Expand Up @@ -2151,7 +2182,7 @@ func TestSetCandidatesUfrag(t *testing.T) {
cand, errCand := NewCandidateHost(&cfg)
require.NoError(t, errCand)

err = agent.addCandidate(context.Background(), cand, dummyConn)
err = agent.addCandidate(context.Background(), cand, dummyConn, agent.gatherGeneration)
require.NoError(t, err)
}

Expand All @@ -2166,6 +2197,46 @@ func TestSetCandidatesUfrag(t *testing.T) {
}
}

func TestAddingCandidatesFromOtherGenerations(t *testing.T) {
var config AgentConfig

agent, err := NewAgent(&config)
require.NoError(t, err)
defer func() {
require.NoError(t, agent.Close())
}()

agent.gatherGeneration = 3

dummyConn := &net.UDPConn{}

for i := 0; i < 5; i++ {
cfg := CandidateHostConfig{
Network: "udp",
Address: "192.168.0.2",
Port: 1000 + i,
Component: 1,
}

cand, errCand := NewCandidateHost(&cfg)
require.NoError(t, errCand)

err = agent.addCandidate(context.Background(), cand, dummyConn, uint64(i)) // nolint:gosec
require.NoError(t, err)
}

actualCandidates, err := agent.GetLocalCandidates()
require.NoError(t, err)
require.Equal(t, 1, len(actualCandidates), "Only the candidate with a matching generation should be added")

ext, ok := actualCandidates[0].GetExtension("generation")
require.True(t, ok)

generation, err := strconv.ParseUint(ext.Value, 10, 64)
require.NoError(t, err)
require.Equal(t, agent.gatherGeneration, generation)
}

func TestAlwaysSentKeepAlive(t *testing.T) { //nolint:cyclop
defer test.CheckRoutines(t)()

Expand Down
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