Add client connection ID methods to quic_packets

gfe-relnote: n/a, adds new currently unused methods
PiperOrigin-RevId: 250704882
Change-Id: I0205e7638c229df39c1bb60661433c34adec5f84

quic/core/quic_packets.cc

diff --git a/quic/core/quic_packets.cc b/quic/core/quic_packets.cc
index 57bda54..738cc6e 100644
--- a/quic/core/quic_packets.cc
+++ b/quic/core/quic_packets.cc
@@ -27,6 +27,16 @@
   return header.source_connection_id;
 }
 
+QuicConnectionId GetClientConnectionIdAsRecipient(
+    const QuicPacketHeader& header,
+    Perspective perspective) {
+  DCHECK(GetQuicRestartFlag(quic_do_not_override_connection_id));
+  if (perspective == Perspective::IS_CLIENT) {
+    return header.destination_connection_id;
+  }
+  return header.source_connection_id;
+}
+
 QuicConnectionId GetServerConnectionIdAsSender(const QuicPacketHeader& header,
                                                Perspective perspective) {
   if (perspective == Perspective::IS_CLIENT ||
@@ -48,6 +58,16 @@
   return header.source_connection_id_included;
 }
 
+QuicConnectionId GetClientConnectionIdAsSender(const QuicPacketHeader& header,
+                                               Perspective perspective) {
+  if (perspective == Perspective::IS_CLIENT ||
+      !GetQuicRestartFlag(quic_do_not_override_connection_id)) {
+    return header.source_connection_id;
+  }
+  QUIC_RESTART_FLAG_COUNT_N(quic_do_not_override_connection_id, 3, 5);
+  return header.destination_connection_id;
+}
+
 QuicConnectionIdIncluded GetClientConnectionIdIncludedAsSender(
     const QuicPacketHeader& header,
     Perspective perspective) {

quic/core/quic_packets.h

diff --git a/quic/core/quic_packets.h b/quic/core/quic_packets.h
index d3c2600..b1964e7 100644
--- a/quic/core/quic_packets.h
+++ b/quic/core/quic_packets.h
@@ -41,6 +41,12 @@
 // Returns the destination connection ID of |header| when |perspective| is
 // client, and the source connection ID when |perspective| is server.
 QUIC_EXPORT_PRIVATE QuicConnectionId
+GetClientConnectionIdAsRecipient(const QuicPacketHeader& header,
+                                 Perspective perspective);
+
+// Returns the destination connection ID of |header| when |perspective| is
+// client, and the source connection ID when |perspective| is server.
+QUIC_EXPORT_PRIVATE QuicConnectionId
 GetServerConnectionIdAsSender(const QuicPacketHeader& header,
                               Perspective perspective);
 
@@ -51,6 +57,12 @@
 GetServerConnectionIdIncludedAsSender(const QuicPacketHeader& header,
                                       Perspective perspective);
 
+// Returns the destination connection ID of |header| when |perspective| is
+// server, and the source connection ID when |perspective| is client.
+QUIC_EXPORT_PRIVATE QuicConnectionId
+GetClientConnectionIdAsSender(const QuicPacketHeader& header,
+                              Perspective perspective);
+
 // Returns the destination connection ID included of |header| when |perspective|
 // is server, and the source connection ID included when |perspective| is
 // client.

quic/core/quic_packets_test.cc

diff --git a/quic/core/quic_packets_test.cc b/quic/core/quic_packets_test.cc
index 9ea369e..be35d20 100644
--- a/quic/core/quic_packets_test.cc
+++ b/quic/core/quic_packets_test.cc
@@ -86,6 +86,31 @@
                                       header, Perspective::IS_CLIENT));
 }
 
+TEST_F(QuicPacketsTest, GetClientConnectionIdAsRecipient) {
+  SetQuicRestartFlag(quic_do_not_override_connection_id, true);
+  QuicPacketHeader header = CreateFakePacketHeader();
+  EXPECT_EQ(TestConnectionId(2),
+            GetClientConnectionIdAsRecipient(header, Perspective::IS_SERVER));
+  EXPECT_EQ(TestConnectionId(1),
+            GetClientConnectionIdAsRecipient(header, Perspective::IS_CLIENT));
+}
+
+TEST_F(QuicPacketsTest, GetClientConnectionIdAsSender) {
+  QuicPacketHeader header = CreateFakePacketHeader();
+  if (!GetQuicRestartFlag(quic_do_not_override_connection_id)) {
+    EXPECT_EQ(TestConnectionId(2),
+              GetClientConnectionIdAsSender(header, Perspective::IS_SERVER));
+    EXPECT_EQ(TestConnectionId(2),
+              GetClientConnectionIdAsSender(header, Perspective::IS_CLIENT));
+    return;
+  }
+
+  EXPECT_EQ(TestConnectionId(1),
+            GetClientConnectionIdAsSender(header, Perspective::IS_SERVER));
+  EXPECT_EQ(TestConnectionId(2),
+            GetClientConnectionIdAsSender(header, Perspective::IS_CLIENT));
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace quic