Pass upstream prefixes to bpf tethering offload
BPF needs upstream prefixes information to filter spoofing IPv6 source
addresses carried in downstream traffic.
We retrieve prefixes from upstream interface's LinkProperties and pass
it to the BpfCoordinator. Forwarding rules will also be updated when
upstream interface's IPv6 link addresses change.
Test: atest TetheringTests
Bug: 261923493
Change-Id: If8cfc3b191e520ca838654d1b5211ab9e9ec021d
diff --git a/Tethering/src/android/net/ip/IpServer.java b/Tethering/src/android/net/ip/IpServer.java
index e030902..8a93e4d 100644
--- a/Tethering/src/android/net/ip/IpServer.java
+++ b/Tethering/src/android/net/ip/IpServer.java
@@ -65,6 +65,7 @@
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
+import com.android.internal.annotations.VisibleForTesting;
import com.android.internal.util.MessageUtils;
import com.android.internal.util.State;
import com.android.internal.util.StateMachine;
@@ -89,6 +90,7 @@
import java.net.UnknownHostException;
import java.util.ArrayList;
import java.util.Arrays;
+import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
@@ -290,6 +292,8 @@
private int mLastIPv6UpstreamIfindex = 0;
private boolean mUpstreamSupportsBpf = false;
+ @NonNull
+ private Set<IpPrefix> mLastIPv6UpstreamPrefixes = Collections.emptySet();
private class MyNeighborEventConsumer implements IpNeighborMonitor.NeighborEventConsumer {
public void accept(NeighborEvent e) {
@@ -761,13 +765,8 @@
if (params.hasDefaultRoute) params.hopLimit = getHopLimit(upstreamIface, ttlAdjustment);
- for (LinkAddress linkAddr : v6only.getLinkAddresses()) {
- if (linkAddr.getPrefixLength() != RFC7421_PREFIX_LENGTH) continue;
-
- final IpPrefix prefix = new IpPrefix(
- linkAddr.getAddress(), linkAddr.getPrefixLength());
- params.prefixes.add(prefix);
-
+ params.prefixes = getTetherableIpv6Prefixes(v6only);
+ for (IpPrefix prefix : params.prefixes) {
final Inet6Address dnsServer = getLocalDnsIpFor(prefix);
if (dnsServer != null) {
params.dnses.add(dnsServer);
@@ -787,9 +786,12 @@
// Not support BPF on virtual upstream interface
final boolean upstreamSupportsBpf = upstreamIface != null && !isVcnInterface(upstreamIface);
- updateIpv6ForwardingRules(mLastIPv6UpstreamIfindex, upstreamIfIndex, upstreamSupportsBpf);
+ final Set<IpPrefix> upstreamPrefixes = params != null ? params.prefixes : Set.of();
+ updateIpv6ForwardingRules(mLastIPv6UpstreamIfindex, mLastIPv6UpstreamPrefixes,
+ upstreamIfIndex, upstreamPrefixes, upstreamSupportsBpf);
mLastIPv6LinkProperties = v6only;
mLastIPv6UpstreamIfindex = upstreamIfIndex;
+ mLastIPv6UpstreamPrefixes = upstreamPrefixes;
mUpstreamSupportsBpf = upstreamSupportsBpf;
if (mDadProxy != null) {
mDadProxy.setUpstreamIface(upstreamIfaceParams);
@@ -897,14 +899,17 @@
return supportsBpf ? ifindex : NO_UPSTREAM;
}
- // Handles updates to IPv6 forwarding rules if the upstream changes.
- private void updateIpv6ForwardingRules(int prevUpstreamIfindex, int upstreamIfindex,
- boolean upstreamSupportsBpf) {
+ // Handles updates to IPv6 forwarding rules if the upstream or its prefixes change.
+ private void updateIpv6ForwardingRules(int prevUpstreamIfindex,
+ @NonNull Set<IpPrefix> prevUpstreamPrefixes, int upstreamIfindex,
+ @NonNull Set<IpPrefix> upstreamPrefixes, boolean upstreamSupportsBpf) {
// If the upstream interface has changed, remove all rules and re-add them with the new
// upstream interface. If upstream is a virtual network, treated as no upstream.
- if (prevUpstreamIfindex != upstreamIfindex) {
+ if (prevUpstreamIfindex != upstreamIfindex
+ || !prevUpstreamPrefixes.equals(upstreamPrefixes)) {
mBpfCoordinator.updateAllIpv6Rules(this, this.mInterfaceParams,
- getInterfaceIndexForRule(upstreamIfindex, upstreamSupportsBpf));
+ getInterfaceIndexForRule(upstreamIfindex, upstreamSupportsBpf),
+ upstreamPrefixes);
}
}
@@ -1309,7 +1314,7 @@
for (String ifname : mUpstreamIfaceSet.ifnames) cleanupUpstreamInterface(ifname);
mUpstreamIfaceSet = null;
mBpfCoordinator.updateAllIpv6Rules(
- IpServer.this, IpServer.this.mInterfaceParams, NO_UPSTREAM);
+ IpServer.this, IpServer.this.mInterfaceParams, NO_UPSTREAM, Set.of());
}
private void cleanupUpstreamInterface(String upstreamIface) {
@@ -1496,4 +1501,21 @@
}
return random;
}
+
+ /** Get IPv6 prefixes from LinkProperties */
+ @NonNull
+ @VisibleForTesting
+ static HashSet<IpPrefix> getTetherableIpv6Prefixes(@NonNull Collection<LinkAddress> addrs) {
+ final HashSet<IpPrefix> prefixes = new HashSet<>();
+ for (LinkAddress linkAddr : addrs) {
+ if (linkAddr.getPrefixLength() != RFC7421_PREFIX_LENGTH) continue;
+ prefixes.add(new IpPrefix(linkAddr.getAddress(), RFC7421_PREFIX_LENGTH));
+ }
+ return prefixes;
+ }
+
+ @NonNull
+ private HashSet<IpPrefix> getTetherableIpv6Prefixes(@NonNull LinkProperties lp) {
+ return getTetherableIpv6Prefixes(lp.getLinkAddresses());
+ }
}