Update the QUIC packet format.

The QUIC packet format has changed again. Update the test to
ensure that the GFE can drop support for the old packet format
without causing all devices to fail CTS.

Packet format changes suggested by dschinazi@.

Bug: 170724836
Test: atest --rerun-until-failure 100 CtsNetTestCasesLatestSdk:MultinetworkApiTest#testNativeDatagramTransmission
Change-Id: I8625ac9a58c55fc19dfb9fdb5f34a89cee40caaf
Merged-In: I8625ac9a58c55fc19dfb9fdb5f34a89cee40caaf
(cherry picked from commit c2b9b83bf353a1fe0669e327fa03ddb024e4f21d)
diff --git a/tests/tests/net/jni/NativeMultinetworkJni.c b/tests/tests/net/jni/NativeMultinetworkJni.c
index 4531f82..b269a8b 100644
--- a/tests/tests/net/jni/NativeMultinetworkJni.c
+++ b/tests/tests/net/jni/NativeMultinetworkJni.c
@@ -177,20 +177,16 @@
     setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO, &timeo, sizeof(timeo));
 
     // For reference see:
-    //     https://tools.ietf.org/html/draft-tsvwg-quic-protocol#section-6.1
+    //     https://datatracker.ietf.org/doc/html/draft-ietf-quic-invariants
     uint8_t quic_packet[1200] = {
-        0x0d,                    // public flags:
-                                 //   - version present (0x01),
-                                 //   - 64bit connection ID (0x0c),
-                                 //   - 1 byte packet number (0x00)
+        0xc0,                    // long header
+        0xaa, 0xda, 0xca, 0xca,  // reserved-space version number
+        0x08,                    // destination connection ID length
         0, 0, 0, 0, 0, 0, 0, 0,  // 64bit connection ID
-        0xaa, 0xda, 0xca, 0xaa,  // reserved-space version number
-        1,                       // 1 byte packet number
-        0x00,                    // private flags
-        0x07,                    // PING frame (cuz why not)
+        0x00,                    // source connection ID length
     };
 
-    arc4random_buf(quic_packet + 1, 8);  // random connection ID
+    arc4random_buf(quic_packet + 6, 8);  // random connection ID
 
     uint8_t response[1500];
     ssize_t sent, rcvd;
@@ -215,7 +211,7 @@
                   i + 1, MAX_RETRIES, rcvd, errnum);
         }
     }
-    if (rcvd < 9) {
+    if (rcvd < 15) {
         ALOGD("QUIC UDP %s: sent=%zd but rcvd=%zd, errno=%d", kPort, sent, rcvd, errnum);
         if (rcvd <= 0) {
             ALOGD("Does this network block UDP port %s?", kPort);
@@ -224,7 +220,7 @@
         return -EPROTO;
     }
 
-    int conn_id_cmp = memcmp(quic_packet + 1, response + 1, 8);
+    int conn_id_cmp = memcmp(quic_packet + 6, response + 7, 8);
     if (conn_id_cmp != 0) {
         ALOGD("sent and received connection IDs do not match");
         close(fd);