Allow variable length connection IDs for unsupported versions
This solves an IETF interop issue where other implementation were failing to trigger version negotiation with a destination connection ID length > 8.
gfe-relnote: allow using QUIC version negotiation with custom connection ID lengths, protected by gfe2_restart_flag_quic_allow_variable_length_connection_id_for_negotiation
PiperOrigin-RevId: 247647676
Change-Id: I5709072f50264f6f207c8e8689d0ed5dd5f6a712
diff --git a/quic/core/quic_utils.cc b/quic/core/quic_utils.cc
index e1caf89..85ce4f2 100644
--- a/quic/core/quic_utils.cc
+++ b/quic/core/quic_utils.cc
@@ -15,6 +15,7 @@
#include "net/third_party/quiche/src/quic/platform/api/quic_arraysize.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_bug_tracker.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_endian.h"
+#include "net/third_party/quiche/src/quic/platform/api/quic_flag_utils.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_flags.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_prefetch.h"
#include "net/third_party/quiche/src/quic/platform/api/quic_uint128.h"
@@ -505,7 +506,16 @@
// static
bool QuicUtils::VariableLengthConnectionIdAllowedForVersion(
QuicTransportVersion version) {
- return version >= QUIC_VERSION_47;
+ if (!GetQuicRestartFlag(
+ quic_allow_variable_length_connection_id_for_negotiation)) {
+ return version >= QUIC_VERSION_47;
+ }
+ QUIC_RESTART_FLAG_COUNT(
+ quic_allow_variable_length_connection_id_for_negotiation);
+ // We allow variable length connection IDs for unsupported versions to
+ // ensure that IETF version negotiation works when other implementations
+ // trigger version negotiation with custom connection ID lengths.
+ return version >= QUIC_VERSION_47 || version == QUIC_VERSION_UNSUPPORTED;
}
// static
