arc: net: Add IP configs to all active network events

This patch adds to all active network events sent to ARC++ over mojo the
complete IP v4 and v6 configurations of the host if they exist. This
relies on the shill Device "IPConfigs" DBUS property which is the only
consistent way to get current v4 and v6 configurations from shill.

This allows to:
  - Correctly set DNS inside Android for the default network and all
  secondary networks.
  - Track inside Android WiFi roaming over the same prefix to avoid
  spurious network disconnection.

BUG=b:112245108
BUG=b:140812279
BUG=b:143247361
BUG=b:143258259
TEST=Deployed Chrome and ARC++. Connected device to eth and wifi.
Manually changed DNS between "Google" and manual entries both both eth
(as the default network) and wifi. Observed that ARC++ consistently gets
correct DNS settings for active network events.

Change-Id: I40b654c5dba0fdf722971b7c12437991b1a5c374
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1892474
Commit-Queue: Hugo Benichi <hugobenichi@google.com>
Reviewed-by: Hidehiko Abe <hidehiko@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712850}

components/arc/net/arc_net_host_impl.cc

@@ -269,6 +269,55 @@ void TranslateONCNetworkTypeDetails(const base::DictionaryValue* dict,
   }
 }
 
+// Add shill's Device properties to the given mojo NetworkConfiguration objects.
+// This adds the network interface and current IP configurations.
+void AddDeviceProperties(arc::mojom::NetworkConfiguration* network,
+                         const std::string& device_path) {
+  const auto* device = GetStateHandler()->GetDeviceState(device_path);
+  if (!device)
+    return;
+
+  network->network_interface = device->interface();
+
+  // IP configurations were already obtained through cached ONC properties.
+  if (network->ip_configs)
+    return;
+
+  std::vector<arc::mojom::IPConfigurationPtr> ip_configs;
+  for (const auto& kv : device->ip_configs()) {
+    auto ip_config = arc::mojom::IPConfiguration::New();
+    if (const std::string* r =
+            kv.second->FindStringPath(shill::kAddressProperty))
+      ip_config->ip_address = *r;
+    if (const std::string* r =
+            kv.second->FindStringPath(shill::kGatewayProperty))
+      ip_config->gateway = *r;
+    ip_config->routing_prefix =
+        kv.second->FindIntPath(shill::kPrefixlenProperty).value_or(0);
+    ip_config->type = (ip_config->routing_prefix < 64)
+                          ? arc::mojom::IPAddressType::IPV4
+                          : arc::mojom::IPAddressType::IPV6;
+    if (const base::Value* dns_list =
+            kv.second->FindListKey(shill::kNameServersProperty)) {
+      for (const auto& dnsValue : dns_list->GetList()) {
+        const std::string& dns = dnsValue.GetString();
+        if (dns.empty())
+          continue;
+
+        // When manually setting DNS, up to 4 addresses can be specified in the
+        // UI. Unspecified entries can show up as 0.0.0.0 and should be removed.
+        if (dns == "0.0.0.0")
+          continue;
+
+        ip_config->name_servers.push_back(dns);
+      }
+    }
+    ip_configs.push_back(std::move(ip_config));
+  }
+
+  network->ip_configs = std::move(ip_configs);
+}
+
 arc::mojom::NetworkConfigurationPtr TranslateONCConfiguration(
     const chromeos::NetworkState* network_state,
     const base::DictionaryValue* dict) {
@@ -305,10 +354,7 @@ arc::mojom::NetworkConfigurationPtr TranslateONCConfiguration(
   if (network_state) {
     mojo->connection_state =
         TranslateConnectionState(network_state->connection_state());
-    const chromeos::DeviceState* device_state =
-        GetStateHandler()->GetDeviceState(network_state->device_path());
-    if (device_state)
-      mojo->network_interface = device_state->interface();
+    AddDeviceProperties(mojo.get(), network_state->device_path());
   }
 
   return mojo;