From 1890801fc35e9d7340dcce7677ec20c447a8bf4f Mon Sep 17 00:00:00 2001
From: Lorenzo Colitti <lorenzo@google.com>
Date: Thu, 29 May 2014 14:05:41 +0900
Subject: [PATCH] Don't break things if a network goes back to CONNECTED.

Currently, if a network goes from CONNECTED to some other "live"
state (e.g., CONNECTING, because it's VERIFYING_POOR_LINK) and
back, ConnectivityService treats it as if a new network had
connected.  This causes it to attempt to create the network
(which fails, since a network with that netid already exists), to
trigger verification, and if the verification succeeds, to tear
down the network because the request it's satisfying is already
satisfied by the network itself.

Instead, if creating the network fails, assume it's because the
network had already been created, and bail out.

Also, when validation completes, ignore NetworkRequests that were
being served by the same NetworkAgent as before.

Bug: 15244052
Change-Id: Ifd73558e5be452d9ef88c64cca429d5f302bf354
---
 .../android/server/ConnectivityService.java   | 22 +++++++++++++++----
 1 file changed, 18 insertions(+), 4 deletions(-)

diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index 1e21e1cc51..5527528fd2 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -5606,16 +5606,23 @@ public class ConnectivityService extends IConnectivityManager.Stub {
         boolean isNewDefault = false;
         if (DBG) log("handleConnectionValidated for "+newNetwork.name());
         // check if any NetworkRequest wants this NetworkAgent
-        // first check if it satisfies the NetworkCapabilities
         ArrayList<NetworkAgentInfo> affectedNetworks = new ArrayList<NetworkAgentInfo>();
         if (VDBG) log(" new Network has: " + newNetwork.networkCapabilities);
         for (NetworkRequestInfo nri : mNetworkRequests.values()) {
+            NetworkAgentInfo currentNetwork = mNetworkForRequestId.get(nri.request.requestId);
+            if (newNetwork == currentNetwork) {
+                if (VDBG) log("Network " + newNetwork.name() + " was already satisfying" +
+                              " request " + nri.request.requestId + ". No change.");
+                keep = true;
+                continue;
+            }
+
+            // check if it satisfies the NetworkCapabilities
             if (VDBG) log("  checking if request is satisfied: " + nri.request);
             if (nri.request.networkCapabilities.satisfiedByNetworkCapabilities(
                     newNetwork.networkCapabilities)) {
                 // next check if it's better than any current network we're using for
                 // this request
-                NetworkAgentInfo currentNetwork = mNetworkForRequestId.get(nri.request.requestId);
                 if (VDBG) {
                     log("currentScore = " +
                             (currentNetwork != null ? currentNetwork.currentScore : 0) +
@@ -5744,12 +5751,19 @@ public class ConnectivityService extends IConnectivityManager.Stub {
         }
 
         if (state == NetworkInfo.State.CONNECTED) {
-            // TODO - check if we want it (optimization)
             try {
+                // This is likely caused by the fact that this network already
+                // exists. An example is when a network goes from CONNECTED to
+                // CONNECTING and back (like wifi on DHCP renew).
+                // TODO: keep track of which networks we've created, or ask netd
+                // to tell us whether we've already created this network or not.
                 mNetd.createNetwork(networkAgent.network.netId);
             } catch (Exception e) {
-                loge("Error creating Network " + networkAgent.network.netId);
+                loge("Error creating network " + networkAgent.network.netId + ": "
+                        + e.getMessage());
+                return;
             }
+
             updateLinkProperties(networkAgent, null);
             notifyNetworkCallbacks(networkAgent, ConnectivityManager.CALLBACK_PRECHECK);
             networkAgent.networkMonitor.sendMessage(NetworkMonitor.CMD_NETWORK_CONNECTED);