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implement connection ID handling for path probe packets (#4935)

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This commit is contained in:
Marten Seemann
2025-01-27 04:06:08 +01:00
committed by GitHub
parent 895faf6dc9
commit e524d0c1ff
2 changed files with 143 additions and 1 deletions
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61
conn_id_manager.go
View File

@@ -10,6 +10,8 @@ import (
"github.com/quic-go/quic-go/internal/wire"
)
type pathID int64
type newConnID struct {
SequenceNumber uint64
ConnectionID protocol.ConnectionID
@@ -19,6 +21,9 @@ type newConnID struct {
type connIDManager struct {
queue list.List[newConnID]
highestProbingID uint64
pathProbing map[pathID]newConnID // initialized lazily
handshakeComplete bool
activeSequenceNumber uint64
highestRetired uint64
@@ -76,13 +81,23 @@ func (h *connIDManager) add(f *wire.NewConnectionIDFrame) error {
}
// If the NEW_CONNECTION_ID frame is reordered, such that its sequence number is smaller than the currently active
// connection ID or if it was already retired, send the RETIRE_CONNECTION_ID frame immediately.
if f.SequenceNumber < h.activeSequenceNumber || f.SequenceNumber < h.highestRetired {
if f.SequenceNumber < max(h.activeSequenceNumber, h.highestProbingID) || f.SequenceNumber < h.highestRetired {
h.queueControlFrame(&wire.RetireConnectionIDFrame{
SequenceNumber: f.SequenceNumber,
})
return nil
}
if f.RetirePriorTo != 0 && h.pathProbing != nil {
for id, entry := range h.pathProbing {
if entry.SequenceNumber < f.RetirePriorTo {
h.queueControlFrame(&wire.RetireConnectionIDFrame{
SequenceNumber: entry.SequenceNumber,
})
delete(h.pathProbing, id)
}
}
}
// Retire elements in the queue.
// Doesn't retire the active connection ID.
if f.RetirePriorTo > h.highestRetired {
@@ -225,6 +240,50 @@ func (h *connIDManager) SetHandshakeComplete() {
h.handshakeComplete = true
}
// GetConnIDForPath retrieves a connection ID for a new path (i.e. not the active one).
// Once a connection ID is allocated for a path, it cannot be used for a different path.
// When called with the same pathID, it will return the same connection ID,
// unless the peer requested that this connection ID be retired.
func (h *connIDManager) GetConnIDForPath(id pathID) (protocol.ConnectionID, bool) {
h.assertNotClosed()
// if we're using zero-length connection IDs, we don't need to change the connection ID
if h.activeConnectionID.Len() == 0 {
return protocol.ConnectionID{}, true
}
if h.pathProbing == nil {
h.pathProbing = make(map[pathID]newConnID)
}
entry, ok := h.pathProbing[id]
if ok {
return entry.ConnectionID, true
}
if h.queue.Len() == 0 {
return protocol.ConnectionID{}, false
}
front := h.queue.Remove(h.queue.Front())
h.pathProbing[id] = front
h.highestProbingID = front.SequenceNumber
return front.ConnectionID, true
}
func (h *connIDManager) RetireConnIDForPath(pathID pathID) {
h.assertNotClosed()
// if we're using zero-length connection IDs, we don't need to change the connection ID
if h.activeConnectionID.Len() == 0 {
return
}
entry, ok := h.pathProbing[pathID]
if !ok {
return
}
h.queueControlFrame(&wire.RetireConnectionIDFrame{
SequenceNumber: entry.SequenceNumber,
})
delete(h.pathProbing, pathID)
}
// Using the connIDManager after it has been closed can have disastrous effects:
// If the connection ID is rotated, a new entry would be inserted into the packet handler map,
// leading to a memory leak of the connection struct.

83
conn_id_manager_test.go
View File

@@ -209,6 +209,78 @@ func TestConnIDManagerConnIDRotation(t *testing.T) {
require.Equal(t, []wire.Frame{&wire.RetireConnectionIDFrame{SequenceNumber: 2}}, frameQueue)
}
func TestConnIDManagerPathMigration(t *testing.T) {
var frameQueue []wire.Frame
m := newConnIDManager(
protocol.ParseConnectionID([]byte{1, 2, 3, 4}),
func(protocol.StatelessResetToken) {},
func(protocol.StatelessResetToken) {},
func(f wire.Frame) { frameQueue = append(frameQueue, f) },
)
// no connection ID available yet
_, ok := m.GetConnIDForPath(1)
require.False(t, ok)
// add a connection ID
require.NoError(t, m.Add(&wire.NewConnectionIDFrame{
SequenceNumber: 1,
ConnectionID: protocol.ParseConnectionID([]byte{4, 3, 2, 1}),
StatelessResetToken: protocol.StatelessResetToken{16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1},
}))
require.NoError(t, m.Add(&wire.NewConnectionIDFrame{
SequenceNumber: 2,
ConnectionID: protocol.ParseConnectionID([]byte{5, 4, 3, 2}),
StatelessResetToken: protocol.StatelessResetToken{16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1},
}))
connID, ok := m.GetConnIDForPath(1)
require.True(t, ok)
require.Equal(t, protocol.ParseConnectionID([]byte{4, 3, 2, 1}), connID)
connID, ok = m.GetConnIDForPath(2)
require.True(t, ok)
require.Equal(t, protocol.ParseConnectionID([]byte{5, 4, 3, 2}), connID)
// asking for the connection for path 1 again returns the same connection ID
connID, ok = m.GetConnIDForPath(1)
require.True(t, ok)
require.Equal(t, protocol.ParseConnectionID([]byte{4, 3, 2, 1}), connID)
// if the connection ID is retired, the path will use another connection ID
require.NoError(t, m.Add(&wire.NewConnectionIDFrame{
SequenceNumber: 3,
RetirePriorTo: 2,
ConnectionID: protocol.ParseConnectionID([]byte{6, 5, 4, 3}),
StatelessResetToken: protocol.StatelessResetToken{16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1},
}))
require.Len(t, frameQueue, 2)
frameQueue = nil
require.Equal(t, protocol.ParseConnectionID([]byte{6, 5, 4, 3}), m.Get())
// the connection ID is not used for new paths
_, ok = m.GetConnIDForPath(3)
require.False(t, ok)
// Manually retiring the connection ID does nothing.
// Path 1 doesn't have a connection ID anymore.
m.RetireConnIDForPath(1)
require.Empty(t, frameQueue)
_, ok = m.GetConnIDForPath(1)
require.False(t, ok)
// only after a new connection ID is added, it will be used for path 1
require.NoError(t, m.Add(&wire.NewConnectionIDFrame{
SequenceNumber: 4,
ConnectionID: protocol.ParseConnectionID([]byte{7, 6, 5, 4}),
StatelessResetToken: protocol.StatelessResetToken{16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1},
}))
connID, ok = m.GetConnIDForPath(1)
require.True(t, ok)
require.Equal(t, protocol.ParseConnectionID([]byte{7, 6, 5, 4}), connID)
// a RETIRE_CONNECTION_ID frame for path 1 is queued when retiring the connection ID
m.RetireConnIDForPath(1)
require.Equal(t, []wire.Frame{&wire.RetireConnectionIDFrame{SequenceNumber: 4}}, frameQueue)
}
func TestConnIDManagerZeroLengthConnectionID(t *testing.T) {
m := newConnIDManager(
protocol.ConnectionID{},
@@ -222,6 +294,17 @@ func TestConnIDManagerZeroLengthConnectionID(t *testing.T) {
require.Equal(t, protocol.ConnectionID{}, m.Get())
}
// for path probing, we don't need to change the connection ID
for id := pathID(1); id < 10; id++ {
connID, ok := m.GetConnIDForPath(id)
require.True(t, ok)
require.Equal(t, protocol.ConnectionID{}, connID)
}
// retiring a connection ID for a path is also a no-op
for id := pathID(1); id < 20; id++ {
m.RetireConnIDForPath(id)
}
require.ErrorIs(t, m.Add(&wire.NewConnectionIDFrame{
SequenceNumber: 1,
ConnectionID: protocol.ConnectionID{},