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Commit a4c95702 authored by Hungming Chen's avatar Hungming Chen
Browse files

[BOT.6] Make BpfCoordinator to support data limit 

The BPF tethering coordinator listens to the forwarding rule
changes for updating data limit which is applied in the following
conditions.
- After adding the first rule on a given upstream, add data limit.
- After removing the last rule on a given upstream, clear data limit.
- The service applies a new data limit on current upstream.

The reason for relying on rule changes is because the Tethering and
IpServer objects have multi-internal state machines. It is hard to
synchronize all of their states.

Note that the data limit cleanup for stopping or switching upstream
relies on offload rules are all removed as well.

Bug: 150736748
Test: manual
Change-Id: I829d36339973f9473fe6b616c48aa288f18d1c46
parent 613af4b2

packages/Tethering/src/android/net/ip/IpServer.java

+15 −35
Original line number Diff line number Diff line
@@ -77,7 +77,6 @@ import java.util.ArrayList; 
import java.util.Arrays;

import java.util.Collections;

import java.util.HashSet;

import java.util.LinkedHashMap;

import java.util.List;

import java.util.Objects;

import java.util.Random;
@@ -272,9 +271,6 @@ public class IpServer extends StateMachine { 
        }

    }



    private final LinkedHashMap<Inet6Address, Ipv6ForwardingRule> mIpv6ForwardingRules =

            new LinkedHashMap<>();



    private final IpNeighborMonitor mIpNeighborMonitor;



    private LinkAddress mIpv4Address;
@@ -843,43 +839,29 @@ public class IpServer extends StateMachine { 
        // TODO: Perhaps remove this protection check.

        if (!mUsingBpfOffload) return;



        try {

            mNetd.tetherOffloadRuleAdd(rule.toTetherOffloadRuleParcel());

            mIpv6ForwardingRules.put(rule.address, rule);

        } catch (RemoteException | ServiceSpecificException e) {

            mLog.e("Could not add IPv6 downstream rule: ", e);

        }

        mBpfCoordinator.tetherOffloadRuleAdd(this, rule);

    }



    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.

    private void removeIpv6ForwardingRule(Ipv6ForwardingRule rule) {

        // TODO: Perhaps remove this protection check.

        // See the related comment in #addIpv6ForwardingRule.

        if (!mUsingBpfOffload) return;



        try {

            mNetd.tetherOffloadRuleRemove(rule.toTetherOffloadRuleParcel());

            if (removeFromMap) {

                mIpv6ForwardingRules.remove(rule.address);

            }

        } catch (RemoteException | ServiceSpecificException e) {

            mLog.e("Could not remove IPv6 downstream rule: ", e);

        }

        mBpfCoordinator.tetherOffloadRuleRemove(this, rule);

    }



    private void clearIpv6ForwardingRules() {

        for (Ipv6ForwardingRule rule : mIpv6ForwardingRules.values()) {

            removeIpv6ForwardingRule(rule, false /*removeFromMap*/);

        }

        mIpv6ForwardingRules.clear();

        if (!mUsingBpfOffload) return;



        mBpfCoordinator.tetherOffloadRuleClear(this);

    }



    // Convenience method to replace a rule with the same rule on a new upstream interface.

    // Allows replacing the rules in one iteration pass without ConcurrentModificationExceptions.

    // Relies on the fact that rules are in a map indexed by IP address.

    private void updateIpv6ForwardingRule(Ipv6ForwardingRule rule, int newIfindex) {

        addIpv6ForwardingRule(rule.onNewUpstream(newIfindex));

        removeIpv6ForwardingRule(rule, false /*removeFromMap*/);

    private void updateIpv6ForwardingRule(int newIfindex) {

        // TODO: Perhaps remove this protection check.

        // See the related comment in #addIpv6ForwardingRule.

        if (!mUsingBpfOffload) return;



        mBpfCoordinator.tetherOffloadRuleUpdate(this, newIfindex);

    }



    // Handles all updates to IPv6 forwarding rules. These can currently change only if the upstream
@@ -895,9 +877,7 @@ public class IpServer extends StateMachine { 
        // If the upstream interface has changed, remove all rules and re-add them with the new

        // upstream interface.

        if (prevUpstreamIfindex != upstreamIfindex) {

            for (Ipv6ForwardingRule rule : mIpv6ForwardingRules.values()) {

                updateIpv6ForwardingRule(rule, upstreamIfindex);

            }

            updateIpv6ForwardingRule(upstreamIfindex);

        }



        // If we're here to process a NeighborEvent, do so now.
@@ -917,7 +897,7 @@ public class IpServer extends StateMachine { 
        if (e.isValid()) {

            addIpv6ForwardingRule(rule);

        } else {

            removeIpv6ForwardingRule(rule, true /*removeFromMap*/);

            removeIpv6ForwardingRule(rule);

        }

    }

packages/Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java

+310 −31

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packages/Tethering/src/com/android/networkstack/tethering/Tethering.java

+2 −2
Original line number Diff line number Diff line
@@ -1709,7 +1709,7 @@ public class Tethering { 
                }



                // TODO: Check the upstream interface if it is managed by BPF offload.

                mBpfCoordinator.start();

                mBpfCoordinator.startPolling();

            }



            @Override
@@ -1722,7 +1722,7 @@ public class Tethering { 
                    mTetherUpstream = null;

                    reportUpstreamChanged(null);

                }

                mBpfCoordinator.stop();

                mBpfCoordinator.stopPolling();

            }



            private boolean updateUpstreamWanted() {

packages/Tethering/tests/unit/src/android/net/ip/IpServerTest.java

+124 −46

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packages/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java

+3 −3

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