joy/android_packages_modules_Connectivity
Watch
1
Fork
You've already forked android_packages_modules_Connectivity
 0
Code Issues Pull requests Projects Releases Wiki Activity

Merge "Obtain the MTU from a socket to the destination" into main

Browse source
This commit is contained in:
Jean Chalard 2023-08-07 05:21:57 +00:00 • committed by Gerrit Code Review
commit f8732eb2ce
1 changed files with 47 additions and 13 deletions
Download patch file Download diff file Expand all files Collapse all files

60
service/src/com/android/server/connectivity/NetworkDiagnostics.java
View file

@ -24,9 +24,12 @@ import static com.android.net.module.util.NetworkStackConstants.ICMP_HEADER_LEN;
import static com.android.net.module.util.NetworkStackConstants.IPV4_HEADER_MIN_LEN;
import static com.android.net.module.util.NetworkStackConstants.IPV6_HEADER_LEN;
import static com.android.net.module.util.NetworkStackConstants.IPV6_MIN_MTU;
import static com.android.net.module.util.NetworkStackConstants.IPV6_MTU;
import static com.android.net.module.util.NetworkStackConstants.IP_MTU;
import android.annotation.NonNull;
import android.annotation.Nullable;
import android.annotation.TargetApi;
import android.net.InetAddresses;
import android.net.LinkAddress;
import android.net.LinkProperties;
@ -35,6 +38,7 @@ import android.net.RouteInfo;
import android.net.TrafficStats;
import android.net.shared.PrivateDnsConfig;
import android.net.util.NetworkConstants;
import android.os.Build;
import android.os.SystemClock;
import android.system.ErrnoException;
import android.system.Os;
@ -213,14 +217,10 @@ public class NetworkDiagnostics {
mLinkProperties.addDnsServer(TEST_DNS6);
}
final int lpMtu = mLinkProperties.getMtu();
final int mtu = lpMtu > 0 ? lpMtu : ETHER_MTU;
for (RouteInfo route : mLinkProperties.getRoutes()) {
if (route.getType() == RouteInfo.RTN_UNICAST && route.hasGateway()) {
InetAddress gateway = route.getGateway();
// Use mtu in the route if exists. Otherwise, use the one in the link property.
final int routeMtu = route.getMtu();
prepareIcmpMeasurements(gateway, (routeMtu > 0) ? routeMtu : mtu);
final InetAddress gateway = route.getGateway();
prepareIcmpMeasurements(gateway);
if (route.isIPv6Default()) {
prepareExplicitSourceIcmpMeasurements(gateway);
}
@ -228,7 +228,7 @@ public class NetworkDiagnostics {
}
for (InetAddress nameserver : mLinkProperties.getDnsServers()) {
prepareIcmpMeasurements(nameserver, mtu);
prepareIcmpMeasurements(nameserver);
prepareDnsMeasurement(nameserver);
// Unlike the DnsResolver which doesn't do certificate validation in opportunistic mode,
@ -285,24 +285,29 @@ public class NetworkDiagnostics {
// calculation.
if (addr instanceof Inet6Address) {
return IPV6_HEADER_LEN + ICMP_HEADER_LEN;
} else {
return IPV4_HEADER_MIN_LEN + ICMP_HEADER_LEN;
}
} catch (UnknownHostException e) {
Log.e(TAG, "Create InetAddress fail(" + target + "): " + e);
throw new AssertionError("Create InetAddress fail(" + target + ")", e);
}
return IPV4_HEADER_MIN_LEN + ICMP_HEADER_LEN;
}
private void prepareIcmpMeasurements(@NonNull InetAddress target, int targetNetworkMtu) {
private void prepareIcmpMeasurements(@NonNull InetAddress target) {
int mtu = getMtuForTarget(target);
// If getMtuForTarget fails, it doesn't matter what mtu is used because connect can't
// succeed anyway
if (mtu <= 0) mtu = mLinkProperties.getMtu();
if (mtu <= 0) mtu = ETHER_MTU;
// Test with different size payload ICMP.
// 1. Test with 0 payload.
addPayloadIcmpMeasurement(target, 0);
final int header = getHeaderLen(target);
// 2. Test with full size MTU.
addPayloadIcmpMeasurement(target, targetNetworkMtu - header);
addPayloadIcmpMeasurement(target, mtu - header);
// 3. If v6, make another measurement with the full v6 min MTU, unless that's what
// was done above.
if ((target instanceof Inet6Address) && (targetNetworkMtu != IPV6_MIN_MTU)) {
if ((target instanceof Inet6Address) && (mtu != IPV6_MIN_MTU)) {
addPayloadIcmpMeasurement(target, IPV6_MIN_MTU - header);
}
}
@ -321,6 +326,35 @@ public class NetworkDiagnostics {
}
}
/**
* Open a socket to the target address and return the mtu from that socket
*
* If the MTU can't be obtained for some reason (e.g. the target is unreachable) this will
* return -1.
*
* @param target the destination address
* @return the mtu to that destination, or -1
*/
// getsockoptInt is S+, but this service code and only installs on S, so it's safe to ignore
// the lint warnings by using @TargetApi.
@TargetApi(Build.VERSION_CODES.S)
private int getMtuForTarget(InetAddress target) {
final int family = target instanceof Inet4Address ? AF_INET : AF_INET6;
try {
final FileDescriptor socket = Os.socket(family, SOCK_DGRAM, 0);
mNetwork.bindSocket(socket);
Os.connect(socket, target, 0);
if (family == AF_INET) {
return Os.getsockoptInt(socket, IPPROTO_IP, IP_MTU);
} else {
return Os.getsockoptInt(socket, IPPROTO_IPV6, IPV6_MTU);
}
} catch (ErrnoException | IOException e) {
Log.e(TAG, "Can't get MTU for destination " + target, e);
return -1;
}
}
private void prepareExplicitSourceIcmpMeasurements(InetAddress target) {
for (LinkAddress l : mLinkProperties.getLinkAddresses()) {
InetAddress source = l.getAddress();