blob: 1817f35f1dcde223f53640f17b9667d7a0dac46f [file] [log] [blame]
/*
* Copyright (C) 2017 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.android.networkstack.tethering;
import static android.net.NetworkStats.DEFAULT_NETWORK_NO;
import static android.net.NetworkStats.METERED_NO;
import static android.net.NetworkStats.ROAMING_NO;
import static android.net.NetworkStats.SET_DEFAULT;
import static android.net.NetworkStats.TAG_NONE;
import static android.net.NetworkStats.UID_ALL;
import static android.net.NetworkStats.UID_TETHERING;
import static android.net.netstats.provider.NetworkStatsProvider.QUOTA_UNLIMITED;
import static android.provider.Settings.Global.TETHER_OFFLOAD_DISABLED;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.app.usage.NetworkStatsManager;
import android.content.ContentResolver;
import android.net.InetAddresses;
import android.net.IpPrefix;
import android.net.LinkAddress;
import android.net.LinkProperties;
import android.net.NetworkStats;
import android.net.NetworkStats.Entry;
import android.net.RouteInfo;
import android.net.netlink.ConntrackMessage;
import android.net.netlink.NetlinkConstants;
import android.net.netlink.NetlinkSocket;
import android.net.netstats.provider.NetworkStatsProvider;
import android.net.util.SharedLog;
import android.os.Handler;
import android.provider.Settings;
import android.system.ErrnoException;
import android.system.OsConstants;
import android.text.TextUtils;
import android.util.Log;
import com.android.internal.annotations.VisibleForTesting;
import com.android.internal.util.IndentingPrintWriter;
import com.android.networkstack.tethering.OffloadHardwareInterface.ForwardedStats;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
/**
* A class to encapsulate the business logic of programming the tethering
* hardware offload interface.
*
* @hide
*/
public class OffloadController {
private static final String TAG = OffloadController.class.getSimpleName();
private static final boolean DBG = false;
private static final String ANYIP = "0.0.0.0";
private static final ForwardedStats EMPTY_STATS = new ForwardedStats();
private static final int DEFAULT_PERFORM_POLL_INTERVAL_MS = 5000;
@VisibleForTesting
enum StatsType {
STATS_PER_IFACE,
STATS_PER_UID,
}
private enum UpdateType { IF_NEEDED, FORCE };
private final Handler mHandler;
private final OffloadHardwareInterface mHwInterface;
private final ContentResolver mContentResolver;
@Nullable
private final OffloadTetheringStatsProvider mStatsProvider;
private final SharedLog mLog;
private final HashMap<String, LinkProperties> mDownstreams;
private boolean mConfigInitialized;
private boolean mControlInitialized;
private LinkProperties mUpstreamLinkProperties;
// The complete set of offload-exempt prefixes passed in via Tethering from
// all upstream and downstream sources.
private Set<IpPrefix> mExemptPrefixes;
// A strictly "smaller" set of prefixes, wherein offload-approved prefixes
// (e.g. downstream on-link prefixes) have been removed and replaced with
// prefixes representing only the locally-assigned IP addresses.
private Set<String> mLastLocalPrefixStrs;
// Maps upstream interface names to offloaded traffic statistics.
// Always contains the latest value received from the hardware for each interface, regardless of
// whether offload is currently running on that interface.
private ConcurrentHashMap<String, ForwardedStats> mForwardedStats =
new ConcurrentHashMap<>(16, 0.75F, 1);
// Maps upstream interface names to interface quotas.
// Always contains the latest value received from the framework for each interface, regardless
// of whether offload is currently running (or is even supported) on that interface. Only
// includes upstream interfaces that have a quota set.
private HashMap<String, Long> mInterfaceQuotas = new HashMap<>();
// Tracking remaining alert quota. Unlike limit quota is subject to interface, the alert
// quota is interface independent and global for tether offload. Note that this is only
// accessed on the handler thread and in the constructor.
private long mRemainingAlertQuota = QUOTA_UNLIMITED;
// Runnable that used to schedule the next stats poll.
private final Runnable mScheduledPollingTask = () -> {
updateStatsForCurrentUpstream();
maybeSchedulePollingStats();
};
private int mNatUpdateCallbacksReceived;
private int mNatUpdateNetlinkErrors;
@NonNull
private final Dependencies mDeps;
// TODO: Put more parameters in constructor into dependency object.
static class Dependencies {
int getPerformPollInterval() {
// TODO: Consider make this configurable.
return DEFAULT_PERFORM_POLL_INTERVAL_MS;
}
}
public OffloadController(Handler h, OffloadHardwareInterface hwi,
ContentResolver contentResolver, NetworkStatsManager nsm, SharedLog log,
@NonNull Dependencies deps) {
mHandler = h;
mHwInterface = hwi;
mContentResolver = contentResolver;
mLog = log.forSubComponent(TAG);
mDownstreams = new HashMap<>();
mExemptPrefixes = new HashSet<>();
mLastLocalPrefixStrs = new HashSet<>();
OffloadTetheringStatsProvider provider = new OffloadTetheringStatsProvider();
try {
nsm.registerNetworkStatsProvider(getClass().getSimpleName(), provider);
} catch (RuntimeException e) {
Log.wtf(TAG, "Cannot register offload stats provider: " + e);
provider = null;
}
mStatsProvider = provider;
mDeps = deps;
}
/** Start hardware offload. */
public boolean start() {
if (started()) return true;
if (isOffloadDisabled()) {
mLog.i("tethering offload disabled");
return false;
}
if (!mConfigInitialized) {
mConfigInitialized = mHwInterface.initOffloadConfig();
if (!mConfigInitialized) {
mLog.i("tethering offload config not supported");
stop();
return false;
}
}
mControlInitialized = mHwInterface.initOffloadControl(
// OffloadHardwareInterface guarantees that these callback
// methods are called on the handler passed to it, which is the
// same as mHandler, as coordinated by the setup in Tethering.
new OffloadHardwareInterface.ControlCallback() {
@Override
public void onStarted() {
if (!started()) return;
mLog.log("onStarted");
}
@Override
public void onStoppedError() {
if (!started()) return;
mLog.log("onStoppedError");
}
@Override
public void onStoppedUnsupported() {
if (!started()) return;
mLog.log("onStoppedUnsupported");
// Poll for statistics and trigger a sweep of tethering
// stats by observers. This might not succeed, but it's
// worth trying anyway. We need to do this because from
// this point on we continue with software forwarding,
// and we need to synchronize stats and limits between
// software and hardware forwarding.
updateStatsForAllUpstreams();
if (mStatsProvider != null) mStatsProvider.pushTetherStats();
}
@Override
public void onSupportAvailable() {
if (!started()) return;
mLog.log("onSupportAvailable");
// [1] Poll for statistics and trigger a sweep of stats
// by observers. We need to do this to ensure that any
// limits set take into account any software tethering
// traffic that has been happening in the meantime.
updateStatsForAllUpstreams();
if (mStatsProvider != null) mStatsProvider.pushTetherStats();
// [2] (Re)Push all state.
computeAndPushLocalPrefixes(UpdateType.FORCE);
pushAllDownstreamState();
pushUpstreamParameters(null);
}
@Override
public void onStoppedLimitReached() {
if (!started()) return;
mLog.log("onStoppedLimitReached");
// We cannot reliably determine on which interface the limit was reached,
// because the HAL interface does not specify it. We cannot just use the
// current upstream, because that might have changed since the time that
// the HAL queued the callback.
// TODO: rev the HAL so that it provides an interface name.
updateStatsForCurrentUpstream();
if (mStatsProvider != null) {
mStatsProvider.pushTetherStats();
// Push stats to service does not cause the service react to it
// immediately. Inform the service about limit reached.
mStatsProvider.notifyLimitReached();
}
}
@Override
public void onNatTimeoutUpdate(int proto,
String srcAddr, int srcPort,
String dstAddr, int dstPort) {
if (!started()) return;
updateNatTimeout(proto, srcAddr, srcPort, dstAddr, dstPort);
}
});
final boolean isStarted = started();
if (!isStarted) {
mLog.i("tethering offload control not supported");
stop();
} else {
mLog.log("tethering offload started");
mNatUpdateCallbacksReceived = 0;
mNatUpdateNetlinkErrors = 0;
maybeSchedulePollingStats();
}
return isStarted;
}
/** Stop hardware offload. */
public void stop() {
// Completely stops tethering offload. After this method is called, it is no longer safe to
// call any HAL method, no callbacks from the hardware will be delivered, and any in-flight
// callbacks must be ignored. Offload may be started again by calling start().
final boolean wasStarted = started();
updateStatsForCurrentUpstream();
mUpstreamLinkProperties = null;
mHwInterface.stopOffloadControl();
mControlInitialized = false;
mConfigInitialized = false;
if (mHandler.hasCallbacks(mScheduledPollingTask)) {
mHandler.removeCallbacks(mScheduledPollingTask);
}
if (wasStarted) mLog.log("tethering offload stopped");
}
private boolean started() {
return mConfigInitialized && mControlInitialized;
}
@VisibleForTesting
class OffloadTetheringStatsProvider extends NetworkStatsProvider {
// These stats must only ever be touched on the handler thread.
@NonNull
private NetworkStats mIfaceStats = new NetworkStats(0L, 0);
@NonNull
private NetworkStats mUidStats = new NetworkStats(0L, 0);
/**
* A helper function that collect tether stats from local hashmap. Note that this does not
* invoke binder call.
*/
@VisibleForTesting
@NonNull
NetworkStats getTetherStats(@NonNull StatsType how) {
NetworkStats stats = new NetworkStats(0L, 0);
final int uid = (how == StatsType.STATS_PER_UID) ? UID_TETHERING : UID_ALL;
for (final Map.Entry<String, ForwardedStats> kv : mForwardedStats.entrySet()) {
final ForwardedStats value = kv.getValue();
final Entry entry = new Entry(kv.getKey(), uid, SET_DEFAULT, TAG_NONE, METERED_NO,
ROAMING_NO, DEFAULT_NETWORK_NO, value.rxBytes, 0L, value.txBytes, 0L, 0L);
stats = stats.addEntry(entry);
}
return stats;
}
@Override
public void onSetLimit(String iface, long quotaBytes) {
// Listen for all iface is necessary since upstream might be changed after limit
// is set.
mHandler.post(() -> {
final Long curIfaceQuota = mInterfaceQuotas.get(iface);
// If the quota is set to unlimited, the value set to HAL is Long.MAX_VALUE,
// which is ~8.4 x 10^6 TiB, no one can actually reach it. Thus, it is not
// useful to set it multiple times.
// Otherwise, the quota needs to be updated to tell HAL to re-count from now even
// if the quota is the same as the existing one.
if (null == curIfaceQuota && QUOTA_UNLIMITED == quotaBytes) return;
if (quotaBytes == QUOTA_UNLIMITED) {
mInterfaceQuotas.remove(iface);
} else {
mInterfaceQuotas.put(iface, quotaBytes);
}
maybeUpdateDataLimit(iface);
});
}
/**
* Push stats to service, but does not cause a force polling. Note that this can only be
* called on the handler thread.
*/
public void pushTetherStats() {
// TODO: remove the accumulated stats and report the diff from HAL directly.
final NetworkStats ifaceDiff =
getTetherStats(StatsType.STATS_PER_IFACE).subtract(mIfaceStats);
final NetworkStats uidDiff =
getTetherStats(StatsType.STATS_PER_UID).subtract(mUidStats);
try {
notifyStatsUpdated(0 /* token */, ifaceDiff, uidDiff);
mIfaceStats = mIfaceStats.add(ifaceDiff);
mUidStats = mUidStats.add(uidDiff);
} catch (RuntimeException e) {
mLog.e("Cannot report network stats: ", e);
}
}
@Override
public void onRequestStatsUpdate(int token) {
// Do not attempt to update stats by querying the offload HAL
// synchronously from a different thread than the Handler thread. http://b/64771555.
mHandler.post(() -> {
updateStatsForCurrentUpstream();
pushTetherStats();
});
}
@Override
public void onSetAlert(long quotaBytes) {
// TODO: Ask offload HAL to notify alert without stopping traffic.
// Post it to handler thread since it access remaining quota bytes.
mHandler.post(() -> {
updateAlertQuota(quotaBytes);
maybeSchedulePollingStats();
});
}
}
private String currentUpstreamInterface() {
return (mUpstreamLinkProperties != null)
? mUpstreamLinkProperties.getInterfaceName() : null;
}
private void maybeUpdateStats(String iface) {
if (TextUtils.isEmpty(iface)) {
return;
}
// Always called on the handler thread.
//
// Use get()/put() instead of updating ForwardedStats in place because we can be called
// concurrently with getTetherStats. In combination with the guarantees provided by
// ConcurrentHashMap, this ensures that getTetherStats always gets the most recent copy of
// the stats for each interface, and does not observe partial writes where rxBytes is
// updated and txBytes is not.
ForwardedStats diff = mHwInterface.getForwardedStats(iface);
final long usedAlertQuota = diff.rxBytes + diff.txBytes;
ForwardedStats base = mForwardedStats.get(iface);
if (base != null) {
diff.add(base);
}
// Update remaining alert quota if it is still positive.
if (mRemainingAlertQuota > 0 && usedAlertQuota > 0) {
// Trim to zero if overshoot.
final long newQuota = Math.max(mRemainingAlertQuota - usedAlertQuota, 0);
updateAlertQuota(newQuota);
}
mForwardedStats.put(iface, diff);
// diff is a new object, just created by getForwardedStats(). Therefore, anyone reading from
// mForwardedStats (i.e., any caller of getTetherStats) will see the new stats immediately.
}
/**
* Update remaining alert quota, fire the {@link NetworkStatsProvider#notifyAlertReached()}
* callback when it reaches zero. This can be invoked either from service setting the alert, or
* {@code maybeUpdateStats} when updating stats. Note that this can be only called on
* handler thread.
*
* @param newQuota non-negative value to indicate the new quota, or
* {@link NetworkStatsProvider#QUOTA_UNLIMITED} to indicate there is no
* quota.
*/
private void updateAlertQuota(long newQuota) {
if (newQuota < QUOTA_UNLIMITED) {
throw new IllegalArgumentException("invalid quota value " + newQuota);
}
if (mRemainingAlertQuota == newQuota) return;
mRemainingAlertQuota = newQuota;
if (mRemainingAlertQuota == 0) {
mLog.i("notifyAlertReached");
if (mStatsProvider != null) mStatsProvider.notifyAlertReached();
}
}
/**
* Schedule polling if needed, this will be stopped if offload has been
* stopped or remaining quota reaches zero or upstream is empty.
* Note that this can be only called on handler thread.
*/
private void maybeSchedulePollingStats() {
if (!isPollingStatsNeeded()) return;
if (mHandler.hasCallbacks(mScheduledPollingTask)) {
mHandler.removeCallbacks(mScheduledPollingTask);
}
mHandler.postDelayed(mScheduledPollingTask, mDeps.getPerformPollInterval());
}
private boolean isPollingStatsNeeded() {
return started() && mRemainingAlertQuota > 0
&& !TextUtils.isEmpty(currentUpstreamInterface());
}
private boolean maybeUpdateDataLimit(String iface) {
// setDataLimit may only be called while offload is occurring on this upstream.
if (!started() || !TextUtils.equals(iface, currentUpstreamInterface())) {
return true;
}
Long limit = mInterfaceQuotas.get(iface);
if (limit == null) {
limit = Long.MAX_VALUE;
}
return mHwInterface.setDataLimit(iface, limit);
}
private void updateStatsForCurrentUpstream() {
maybeUpdateStats(currentUpstreamInterface());
}
private void updateStatsForAllUpstreams() {
// In practice, there should only ever be a single digit number of
// upstream interfaces over the lifetime of an active tethering session.
// Roughly speaking, imagine a very ambitious one or two of each of the
// following interface types: [ "rmnet_data", "wlan", "eth", "rndis" ].
for (Map.Entry<String, ForwardedStats> kv : mForwardedStats.entrySet()) {
maybeUpdateStats(kv.getKey());
}
}
/** Set current tethering upstream LinkProperties. */
public void setUpstreamLinkProperties(LinkProperties lp) {
if (!started() || Objects.equals(mUpstreamLinkProperties, lp)) return;
final String prevUpstream = currentUpstreamInterface();
mUpstreamLinkProperties = (lp != null) ? new LinkProperties(lp) : null;
// Make sure we record this interface in the ForwardedStats map.
final String iface = currentUpstreamInterface();
if (!TextUtils.isEmpty(iface)) mForwardedStats.putIfAbsent(iface, EMPTY_STATS);
maybeSchedulePollingStats();
// TODO: examine return code and decide what to do if programming
// upstream parameters fails (probably just wait for a subsequent
// onOffloadEvent() callback to tell us offload is available again and
// then reapply all state).
computeAndPushLocalPrefixes(UpdateType.IF_NEEDED);
pushUpstreamParameters(prevUpstream);
}
/** Set local prefixes. */
public void setLocalPrefixes(Set<IpPrefix> localPrefixes) {
mExemptPrefixes = localPrefixes;
if (!started()) return;
computeAndPushLocalPrefixes(UpdateType.IF_NEEDED);
}
/** Update current downstream LinkProperties. */
public void notifyDownstreamLinkProperties(LinkProperties lp) {
final String ifname = lp.getInterfaceName();
final LinkProperties oldLp = mDownstreams.put(ifname, new LinkProperties(lp));
if (Objects.equals(oldLp, lp)) return;
if (!started()) return;
pushDownstreamState(oldLp, lp);
}
private void pushDownstreamState(LinkProperties oldLp, LinkProperties newLp) {
final String ifname = newLp.getInterfaceName();
final List<RouteInfo> oldRoutes =
(oldLp != null) ? oldLp.getRoutes() : Collections.EMPTY_LIST;
final List<RouteInfo> newRoutes = newLp.getRoutes();
// For each old route, if not in new routes: remove.
for (RouteInfo ri : oldRoutes) {
if (shouldIgnoreDownstreamRoute(ri)) continue;
if (!newRoutes.contains(ri)) {
mHwInterface.removeDownstreamPrefix(ifname, ri.getDestination().toString());
}
}
// For each new route, if not in old routes: add.
for (RouteInfo ri : newRoutes) {
if (shouldIgnoreDownstreamRoute(ri)) continue;
if (!oldRoutes.contains(ri)) {
mHwInterface.addDownstreamPrefix(ifname, ri.getDestination().toString());
}
}
}
private void pushAllDownstreamState() {
for (LinkProperties lp : mDownstreams.values()) {
pushDownstreamState(null, lp);
}
}
/** Remove downstream interface from offload hardware. */
public void removeDownstreamInterface(String ifname) {
final LinkProperties lp = mDownstreams.remove(ifname);
if (lp == null) return;
if (!started()) return;
for (RouteInfo route : lp.getRoutes()) {
if (shouldIgnoreDownstreamRoute(route)) continue;
mHwInterface.removeDownstreamPrefix(ifname, route.getDestination().toString());
}
}
private boolean isOffloadDisabled() {
final int defaultDisposition = mHwInterface.getDefaultTetherOffloadDisabled();
return (Settings.Global.getInt(
mContentResolver, TETHER_OFFLOAD_DISABLED, defaultDisposition) != 0);
}
private boolean pushUpstreamParameters(String prevUpstream) {
final String iface = currentUpstreamInterface();
if (TextUtils.isEmpty(iface)) {
final boolean rval = mHwInterface.setUpstreamParameters("", ANYIP, ANYIP, null);
// Update stats after we've told the hardware to stop forwarding so
// we don't miss packets.
maybeUpdateStats(prevUpstream);
return rval;
}
// A stacked interface cannot be an upstream for hardware offload.
// Consequently, we examine only the primary interface name, look at
// getAddresses() rather than getAllAddresses(), and check getRoutes()
// rather than getAllRoutes().
final ArrayList<String> v6gateways = new ArrayList<>();
String v4addr = null;
String v4gateway = null;
for (InetAddress ip : mUpstreamLinkProperties.getAddresses()) {
if (ip instanceof Inet4Address) {
v4addr = ip.getHostAddress();
break;
}
}
// Find the gateway addresses of all default routes of either address family.
for (RouteInfo ri : mUpstreamLinkProperties.getRoutes()) {
if (!ri.hasGateway()) continue;
final String gateway = ri.getGateway().getHostAddress();
final InetAddress address = ri.getDestination().getAddress();
if (ri.isDefaultRoute() && address instanceof Inet4Address) {
v4gateway = gateway;
} else if (ri.isDefaultRoute() && address instanceof Inet6Address) {
v6gateways.add(gateway);
}
}
boolean success = mHwInterface.setUpstreamParameters(
iface, v4addr, v4gateway, (v6gateways.isEmpty() ? null : v6gateways));
if (!success) {
return success;
}
// Update stats after we've told the hardware to change routing so we don't miss packets.
maybeUpdateStats(prevUpstream);
// Data limits can only be set once offload is running on the upstream.
success = maybeUpdateDataLimit(iface);
if (!success) {
// If we failed to set a data limit, don't use this upstream, because we don't want to
// blow through the data limit that we were told to apply.
mLog.log("Setting data limit for " + iface + " failed, disabling offload.");
stop();
}
return success;
}
private boolean computeAndPushLocalPrefixes(UpdateType how) {
final boolean force = (how == UpdateType.FORCE);
final Set<String> localPrefixStrs = computeLocalPrefixStrings(
mExemptPrefixes, mUpstreamLinkProperties);
if (!force && mLastLocalPrefixStrs.equals(localPrefixStrs)) return true;
mLastLocalPrefixStrs = localPrefixStrs;
return mHwInterface.setLocalPrefixes(new ArrayList<>(localPrefixStrs));
}
// TODO: Factor in downstream LinkProperties once that information is available.
private static Set<String> computeLocalPrefixStrings(
Set<IpPrefix> localPrefixes, LinkProperties upstreamLinkProperties) {
// Create an editable copy.
final Set<IpPrefix> prefixSet = new HashSet<>(localPrefixes);
// TODO: If a downstream interface (not currently passed in) is reusing
// the /64 of the upstream (64share) then:
//
// [a] remove that /64 from the local prefixes
// [b] add in /128s for IP addresses on the downstream interface
// [c] add in /128s for IP addresses on the upstream interface
//
// Until downstream information is available here, simply add /128s from
// the upstream network; they'll just be redundant with their /64.
if (upstreamLinkProperties != null) {
for (LinkAddress linkAddr : upstreamLinkProperties.getLinkAddresses()) {
if (!linkAddr.isGlobalPreferred()) continue;
final InetAddress ip = linkAddr.getAddress();
if (!(ip instanceof Inet6Address)) continue;
prefixSet.add(new IpPrefix(ip, 128));
}
}
final HashSet<String> localPrefixStrs = new HashSet<>();
for (IpPrefix pfx : prefixSet) localPrefixStrs.add(pfx.toString());
return localPrefixStrs;
}
private static boolean shouldIgnoreDownstreamRoute(RouteInfo route) {
// Ignore any link-local routes.
final IpPrefix destination = route.getDestination();
final LinkAddress linkAddr = new LinkAddress(destination.getAddress(),
destination.getPrefixLength());
if (!linkAddr.isGlobalPreferred()) return true;
return false;
}
/** Dump information. */
public void dump(IndentingPrintWriter pw) {
if (isOffloadDisabled()) {
pw.println("Offload disabled");
return;
}
final boolean isStarted = started();
pw.println("Offload HALs " + (isStarted ? "started" : "not started"));
LinkProperties lp = mUpstreamLinkProperties;
String upstream = (lp != null) ? lp.getInterfaceName() : null;
pw.println("Current upstream: " + upstream);
pw.println("Exempt prefixes: " + mLastLocalPrefixStrs);
pw.println("NAT timeout update callbacks received during the "
+ (isStarted ? "current" : "last")
+ " offload session: "
+ mNatUpdateCallbacksReceived);
pw.println("NAT timeout update netlink errors during the "
+ (isStarted ? "current" : "last")
+ " offload session: "
+ mNatUpdateNetlinkErrors);
}
private void updateNatTimeout(
int proto, String srcAddr, int srcPort, String dstAddr, int dstPort) {
final String protoName = protoNameFor(proto);
if (protoName == null) {
mLog.e("Unknown NAT update callback protocol: " + proto);
return;
}
final Inet4Address src = parseIPv4Address(srcAddr);
if (src == null) {
mLog.e("Failed to parse IPv4 address: " + srcAddr);
return;
}
if (!isValidUdpOrTcpPort(srcPort)) {
mLog.e("Invalid src port: " + srcPort);
return;
}
final Inet4Address dst = parseIPv4Address(dstAddr);
if (dst == null) {
mLog.e("Failed to parse IPv4 address: " + dstAddr);
return;
}
if (!isValidUdpOrTcpPort(dstPort)) {
mLog.e("Invalid dst port: " + dstPort);
return;
}
mNatUpdateCallbacksReceived++;
final String natDescription = String.format("%s (%s, %s) -> (%s, %s)",
protoName, srcAddr, srcPort, dstAddr, dstPort);
if (DBG) {
mLog.log("NAT timeout update: " + natDescription);
}
final int timeoutSec = connectionTimeoutUpdateSecondsFor(proto);
final byte[] msg = ConntrackMessage.newIPv4TimeoutUpdateRequest(
proto, src, srcPort, dst, dstPort, timeoutSec);
try {
NetlinkSocket.sendOneShotKernelMessage(OsConstants.NETLINK_NETFILTER, msg);
} catch (ErrnoException e) {
mNatUpdateNetlinkErrors++;
mLog.e("Error updating NAT conntrack entry >" + natDescription + "<: " + e
+ ", msg: " + NetlinkConstants.hexify(msg));
mLog.log("NAT timeout update callbacks received: " + mNatUpdateCallbacksReceived);
mLog.log("NAT timeout update netlink errors: " + mNatUpdateNetlinkErrors);
}
}
private static Inet4Address parseIPv4Address(String addrString) {
try {
final InetAddress ip = InetAddresses.parseNumericAddress(addrString);
// TODO: Consider other sanitization steps here, including perhaps:
// not eql to 0.0.0.0
// not within 169.254.0.0/16
// not within ::ffff:0.0.0.0/96
// not within ::/96
// et cetera.
if (ip instanceof Inet4Address) {
return (Inet4Address) ip;
}
} catch (IllegalArgumentException iae) { }
return null;
}
private static String protoNameFor(int proto) {
// OsConstants values are not constant expressions; no switch statement.
if (proto == OsConstants.IPPROTO_UDP) {
return "UDP";
} else if (proto == OsConstants.IPPROTO_TCP) {
return "TCP";
}
return null;
}
private static int connectionTimeoutUpdateSecondsFor(int proto) {
// TODO: Replace this with more thoughtful work, perhaps reading from
// and maybe writing to any required
//
// /proc/sys/net/netfilter/nf_conntrack_tcp_timeout_*
// /proc/sys/net/netfilter/nf_conntrack_udp_timeout{,_stream}
//
// entries. TBD.
if (proto == OsConstants.IPPROTO_TCP) {
// Cf. /proc/sys/net/netfilter/nf_conntrack_tcp_timeout_established
return 432000;
} else {
// Cf. /proc/sys/net/netfilter/nf_conntrack_udp_timeout_stream
return 180;
}
}
private static boolean isValidUdpOrTcpPort(int port) {
return port > 0 && port < 65536;
}
}