Set accept_ra_rt_info_max_plen to 64 before enabling IPv6 interfaces

This patch tries to change accept_ra_rt_info_max_plen to 64 from its
default value of 0 on kernels that support router advertisements with
route information options. The code fails silently on older unsupported
platforms.

Also factor existing startIPv6() code into a self documenting function
enableInterfaceIpv6PrivacyExtensions()

Bug: 33333670
Test: as follows
    - build sailfish
    - flashed
    - booted
    - runtest frameworks-net passes
    - runtest frameworks-wifi passes

Change-Id: I10ec83b9e04836089477d74417b7222499820066

diff --git a/services/core/java/com/android/server/connectivity/tethering/IPv6TetheringInterfaceServices.java b/services/core/java/com/android/server/connectivity/tethering/IPv6TetheringInterfaceServices.java
index dec2f77..8c6430c 100644 (file)
--- a/services/core/java/com/android/server/connectivity/tethering/IPv6TetheringInterfaceServices.java
+++ b/services/core/java/com/android/server/connectivity/tethering/IPv6TetheringInterfaceServices.java
@@ -16,6 +16,8 @@
 
 package com.android.server.connectivity.tethering;
 
+import static android.net.util.NetworkConstants.RFC7421_PREFIX_LENGTH;
+
 import android.net.INetd;
 import android.net.IpPrefix;
 import android.net.LinkAddress;
@@ -48,7 +50,6 @@ import java.util.Objects;
 public class IPv6TetheringInterfaceServices {
     private static final String TAG = IPv6TetheringInterfaceServices.class.getSimpleName();
     private static final IpPrefix LINK_LOCAL_PREFIX = new IpPrefix("fe80::/64");
-    private static final int RFC7421_IP_PREFIX_LENGTH = 64;
 
     private final String mIfName;
     private final INetworkManagementService mNMService;
@@ -124,7 +125,7 @@ public class IPv6TetheringInterfaceServices {
             params.hasDefaultRoute = v6only.hasIPv6DefaultRoute();
 
             for (LinkAddress linkAddr : v6only.getLinkAddresses()) {
-                if (linkAddr.getPrefixLength() != RFC7421_IP_PREFIX_LENGTH) continue;
+                if (linkAddr.getPrefixLength() != RFC7421_PREFIX_LENGTH) continue;
 
                 final IpPrefix prefix = new IpPrefix(
                         linkAddr.getAddress(), linkAddr.getPrefixLength());
@@ -206,7 +207,7 @@ public class IPv6TetheringInterfaceServices {
             for (Inet6Address dns : deprecatedDnses) {
                 final String dnsString = dns.getHostAddress();
                 try {
-                    netd.interfaceDelAddress(mIfName, dnsString, RFC7421_IP_PREFIX_LENGTH);
+                    netd.interfaceDelAddress(mIfName, dnsString, RFC7421_PREFIX_LENGTH);
                 } catch (ServiceSpecificException | RemoteException e) {
                     Log.e(TAG, "Failed to remove local dns IP: " + dnsString, e);
                 }
@@ -223,7 +224,7 @@ public class IPv6TetheringInterfaceServices {
             for (Inet6Address dns : addedDnses) {
                 final String dnsString = dns.getHostAddress();
                 try {
-                    netd.interfaceAddAddress(mIfName, dnsString, RFC7421_IP_PREFIX_LENGTH);
+                    netd.interfaceAddAddress(mIfName, dnsString, RFC7421_PREFIX_LENGTH);
                 } catch (ServiceSpecificException | RemoteException e) {
                     Log.e(TAG, "Failed to add local dns IP: " + dnsString, e);
                     newDnses.remove(dns);

diff --git a/services/net/java/android/net/ip/IpManager.java b/services/net/java/android/net/ip/IpManager.java
index 3e3a19b..c670782 100644 (file)
--- a/services/net/java/android/net/ip/IpManager.java
+++ b/services/net/java/android/net/ip/IpManager.java
@@ -16,6 +16,8 @@
 
 package android.net.ip;
 
+import static android.net.util.NetworkConstants.RFC7421_PREFIX_LENGTH;
+
 import com.android.internal.util.MessageUtils;
 import com.android.internal.util.WakeupMessage;
 
@@ -42,6 +44,7 @@ import android.os.RemoteException;
 import android.os.ServiceManager;
 import android.os.ServiceSpecificException;
 import android.os.SystemClock;
+import android.system.OsConstants;
 import android.text.TextUtils;
 import android.util.LocalLog;
 import android.util.Log;
@@ -1028,15 +1031,36 @@ public class IpManager extends StateMachine {
         return true;
     }
 
-    private boolean startIPv6() {
-        // Set privacy extensions.
+    private void enableInterfaceIPv6PrivacyExtensions() {
         final String PREFER_TEMPADDRS = "2";
-        try {
-            NetdService.run((INetd netd) -> {
+        NetdService.run((INetd netd) -> {
                 netd.setProcSysNet(
-                        INetd.IPV6, INetd.CONF, mInterfaceName, "use_tempaddr",
-                        PREFER_TEMPADDRS);
+                        INetd.IPV6, INetd.CONF, mInterfaceName, "use_tempaddr", PREFER_TEMPADDRS);
             });
+    }
+
+    private void setInterfaceIPv6RaRtInfoMaxPlen(int plen) {
+        // Setting RIO max plen is best effort. Catch and ignore most exceptions.
+        try {
+            NetdService.run((INetd netd) -> {
+                    netd.setProcSysNet(
+                            INetd.IPV6, INetd.CONF, mInterfaceName, "accept_ra_rt_info_max_plen",
+                            Integer.toString(plen));
+                });
+        } catch (ServiceSpecificException e) {
+            // Old kernel versions without support for RIOs do not export accept_ra_rt_info_max_plen
+            // in the /proc filesystem. If the kernel supports RIOs we should never see any other
+            // type of error.
+            if (e.errorCode != OsConstants.ENOENT) {
+                logError("unexpected error setting accept_ra_rt_info_max_plen %s", e);
+            }
+        }
+    }
+
+    private boolean startIPv6() {
+        try {
+            enableInterfaceIPv6PrivacyExtensions();
+            setInterfaceIPv6RaRtInfoMaxPlen(RFC7421_PREFIX_LENGTH);
             mNwService.enableIpv6(mInterfaceName);
         } catch (IllegalStateException|RemoteException|ServiceSpecificException e) {
             logError("Unable to change interface settings: %s", e);

diff --git a/services/net/java/android/net/util/NetworkConstants.java b/services/net/java/android/net/util/NetworkConstants.java
index 362f757..26f3050 100644 (file)
--- a/services/net/java/android/net/util/NetworkConstants.java
+++ b/services/net/java/android/net/util/NetworkConstants.java
@@ -97,6 +97,7 @@ public final class NetworkConstants {
     public static final int IPV6_SRC_ADDR_OFFSET = 8;
     public static final int IPV6_DST_ADDR_OFFSET = 24;
     public static final int IPV6_ADDR_LEN = 16;
+    public static final int RFC7421_PREFIX_LENGTH = 64;
 
     /**
      * ICMPv6 constants.