464xlat: use a gatewayed route, not point-to-point
Various applications such as Skype and our legacy VPN code
do not understand routes pointed directly at point-to-point
interfaces and require a default gateway IPv4 address in
order to function.
Grudgingly accept that routes without default gateways Are Hard
and use gatewayed routes instead. This causes routing to go from:
default dev clat4 scope link
to:
default via 192.0.0.4 dev clat4 scope link
192.0.0.4 dev clat4 scope link
and those apps now work.
Bug: 9597256
Bug: 9597516
Change-Id: I7b7890873802d3cb99affd6eb70b8ab75e7a2cf6
diff --git a/services/java/com/android/server/connectivity/Nat464Xlat.java b/services/java/com/android/server/connectivity/Nat464Xlat.java
index 59403c5..a15d678 100644
--- a/services/java/com/android/server/connectivity/Nat464Xlat.java
+++ b/services/java/com/android/server/connectivity/Nat464Xlat.java
@@ -147,17 +147,24 @@
" added, mIsRunning = " + mIsRunning + " -> true");
mIsRunning = true;
- // Get the network configuration of the clat interface, store it
- // in our link properties, and stack it on top of the interface
- // it's running on.
+ // Create the LinkProperties for the clat interface by fetching the
+ // IPv4 address for the interface and adding an IPv4 default route,
+ // then stack the LinkProperties on top of the link it's running on.
+ // Although the clat interface is a point-to-point tunnel, we don't
+ // point the route directly at the interface because some apps don't
+ // understand routes without gateways (see, e.g., http://b/9597256
+ // http://b/9597516). Instead, set the next hop of the route to the
+ // clat IPv4 address itself (for those apps, it doesn't matter what
+ // the IP of the gateway is, only that there is one).
try {
InterfaceConfiguration config = mNMService.getInterfaceConfig(iface);
+ LinkAddress clatAddress = config.getLinkAddress();
mLP.clear();
mLP.setInterfaceName(iface);
- RouteInfo ipv4Default = new RouteInfo(new LinkAddress(Inet4Address.ANY, 0), null,
- iface);
+ RouteInfo ipv4Default = new RouteInfo(new LinkAddress(Inet4Address.ANY, 0),
+ clatAddress.getAddress(), iface);
mLP.addRoute(ipv4Default);
- mLP.addLinkAddress(config.getLinkAddress());
+ mLP.addLinkAddress(clatAddress);
mTracker.addStackedLink(mLP);
Slog.i(TAG, "Adding stacked link. tracker LP: " +
mTracker.getLinkProperties());
