commit 443e1eb4f027fb155710a2f741546044efb69cf9
author Xiao Ma <xiaom@google.com> Thu Sep 21 22:18:38 2023 +0900
committer Xiao Ma <xiaom@google.com> Mon Sep 25 13:35:51 2023 +0900
tree 144e27f30e3ae7b1a5d06111d45ea092af458132
parent 1762647ae260c1072cf6ee3e9cc79f073c84910c

Send the first DHCPv6 message with a delay to avoid synchronization.

Per RFC8415 section 18.2.1 the first Solicit message from the client
on the interface should be delayed by a random amount of time between
0 and SOL_MAX_DELAY(1s). Send the first message with a delay in the
PacketRetransmitState, the delay can be 0, depends on the substate.

Bug: 260934173
Test: TH
Change-Id: If5aeaa0118515d9de3134c636871a8771cf0b148

src/android/net/dhcp6/Dhcp6Client.java

diff --git a/src/android/net/dhcp6/Dhcp6Client.java b/src/android/net/dhcp6/Dhcp6Client.java
index 0c3a903..ce63d86 100644
--- a/src/android/net/dhcp6/Dhcp6Client.java
+++ b/src/android/net/dhcp6/Dhcp6Client.java
@@ -236,11 +236,13 @@
         private long mRetransTimeout = -1;
         private int mRetransCount = 0;
         private long mMaxRetransDurationMillis = 0;
+        private final long mInitialDelayMillis;
         private final long mInitialRetransTimeMillis;
         private final long mMaxRetransTimeMillis;
         private final int mMaxRetransCount;
 
-        PacketRetransmittingState(final long irt, final long mrt, final int mrc) {
+        PacketRetransmittingState(final long delay, final long irt, final long mrt, final int mrc) {
+            mInitialDelayMillis = delay;
             mInitialRetransTimeMillis = irt;
             mMaxRetransTimeMillis = mrt;
             mMaxRetransCount = mrc;
@@ -249,7 +251,7 @@
         @Override
         public void enter() {
             super.enter();
-            sendMessage(CMD_KICK);
+            sendMessageDelayed(CMD_KICK, mInitialDelayMillis);
         }
 
         @Override
@@ -495,7 +497,7 @@
     class SolicitState extends PacketRetransmittingState {
         SolicitState() {
             // TODO: use the actual constants.
-            super((long) 0/* IRT */, (long) 0 /* MRT */, 0 /* MRC */);
+            super((long) 0 /* delay */, (long) 0/* IRT */, (long) 0 /* MRT */, 0 /* MRC */);
         }
 
         @Override
@@ -544,7 +546,7 @@
     class RequestState extends PacketRetransmittingState {
         RequestState() {
             // TODO: use the actual constants.
-            super((long) 0/* IRT */, (long) 0 /* MRT */, 0 /* MRC */);
+            super((long) 0 /* delay */, (long) 0/* IRT */, (long) 0 /* MRT */, 0 /* MRC */);
         }
 
         @Override
@@ -669,7 +671,7 @@
     abstract class ReacquireState extends PacketRetransmittingState {
         ReacquireState() {
             // TODO: use the actual constants.
-            super((long) 0/* IRT */, (long) 0 /* MRT */, 0 /* MRC */);
+            super((long) 0 /* delay */, (long) 0/* IRT */, (long) 0 /* MRT */, 0 /* MRC */);
         }
 
         @Override