Use device option to control BPF offload features
If BPF offload device config is not enabled:
- Does not add/remove offload forwarding rules through disabling IP
neighbor monitor.
- Does not apply the RA MTU reduction.
Bug: 149997301
Test: atest IpServerTest
Change-Id: I2d6f80f0229f580c4b16243a064e889a6c37f77a
diff --git a/Tethering/src/android/net/ip/IpServer.java b/Tethering/src/android/net/ip/IpServer.java
index 83727bc..ca485f5 100644
--- a/Tethering/src/android/net/ip/IpServer.java
+++ b/Tethering/src/android/net/ip/IpServer.java
@@ -227,6 +227,7 @@
private final int mInterfaceType;
private final LinkProperties mLinkProperties;
private final boolean mUsingLegacyDhcp;
+ private final boolean mUsingBpfOffload;
private final Dependencies mDeps;
@@ -304,7 +305,8 @@
public IpServer(
String ifaceName, Looper looper, int interfaceType, SharedLog log,
- INetd netd, Callback callback, boolean usingLegacyDhcp, Dependencies deps) {
+ INetd netd, Callback callback, boolean usingLegacyDhcp, boolean usingBpfOffload,
+ Dependencies deps) {
super(ifaceName, looper);
mLog = log.forSubComponent(ifaceName);
mNetd = netd;
@@ -314,6 +316,7 @@
mInterfaceType = interfaceType;
mLinkProperties = new LinkProperties();
mUsingLegacyDhcp = usingLegacyDhcp;
+ mUsingBpfOffload = usingBpfOffload;
mDeps = deps;
resetLinkProperties();
mLastError = TetheringManager.TETHER_ERROR_NO_ERROR;
@@ -321,8 +324,15 @@
mIpNeighborMonitor = mDeps.getIpNeighborMonitor(getHandler(), mLog,
new MyNeighborEventConsumer());
- if (!mIpNeighborMonitor.start()) {
- mLog.e("Failed to create IpNeighborMonitor on " + mIfaceName);
+
+ // IP neighbor monitor monitors the neighbor event for adding/removing offload
+ // forwarding rules per client. If BPF offload is not supported, don't start listening
+ // neighbor events. See updateIpv6ForwardingRules, addIpv6ForwardingRule,
+ // removeIpv6ForwardingRule.
+ if (mUsingBpfOffload) {
+ if (!mIpNeighborMonitor.start()) {
+ mLog.e("Failed to create IpNeighborMonitor on " + mIfaceName);
+ }
}
mInitialState = new InitialState();
@@ -715,12 +725,12 @@
final String upstreamIface = v6only.getInterfaceName();
params = new RaParams();
- // We advertise an mtu lower by 16, which is the closest multiple of 8 >= 14,
- // the ethernet header size. This makes kernel ebpf tethering offload happy.
- // This hack should be reverted once we have the kernel fixed up.
+ // When BPF offload is enabled, we advertise an mtu lower by 16, which is the closest
+ // multiple of 8 >= 14, the ethernet header size. This makes kernel ebpf tethering
+ // offload happy. This hack should be reverted once we have the kernel fixed up.
// Note: this will automatically clamp to at least 1280 (ipv6 minimum mtu)
// see RouterAdvertisementDaemon.java putMtu()
- params.mtu = v6only.getMtu() - 16;
+ params.mtu = mUsingBpfOffload ? v6only.getMtu() - 16 : v6only.getMtu();
params.hasDefaultRoute = v6only.hasIpv6DefaultRoute();
if (params.hasDefaultRoute) params.hopLimit = getHopLimit(upstreamIface);
@@ -844,6 +854,11 @@
}
private void addIpv6ForwardingRule(Ipv6ForwardingRule rule) {
+ // Theoretically, we don't need this check because IP neighbor monitor doesn't start if BPF
+ // offload is disabled. Add this check just in case.
+ // TODO: Perhaps remove this protection check.
+ if (!mUsingBpfOffload) return;
+
try {
mNetd.tetherOffloadRuleAdd(rule.toTetherOffloadRuleParcel());
mIpv6ForwardingRules.put(rule.address, rule);
@@ -853,6 +868,11 @@
}
private void removeIpv6ForwardingRule(Ipv6ForwardingRule rule, boolean removeFromMap) {
+ // Theoretically, we don't need this check because IP neighbor monitor doesn't start if BPF
+ // offload is disabled. Add this check just in case.
+ // TODO: Perhaps remove this protection check.
+ if (!mUsingBpfOffload) return;
+
try {
mNetd.tetherOffloadRuleRemove(rule.toTetherOffloadRuleParcel());
if (removeFromMap) {