Support DHCP replies with multiple default gateways.

Just use the first one for compatibility with the legacy client.

Bug: 23975855
Change-Id: Id6a0b0de32e8947c12c02eb9a3be417e2f82c99a

diff --git a/services/net/java/android/net/dhcp/DhcpAckPacket.java b/services/net/java/android/net/dhcp/DhcpAckPacket.java
index 334f708..df44b11 100644 (file)
--- a/services/net/java/android/net/dhcp/DhcpAckPacket.java
+++ b/services/net/java/android/net/dhcp/DhcpAckPacket.java
@@ -46,7 +46,7 @@ class DhcpAckPacket extends DhcpPacket {
 
         return s + " ACK: your new IP " + mYourIp +
                 ", netmask " + mSubnetMask +
-                ", gateway " + mGateway + dnsServers +
+                ", gateways " + mGateways + dnsServers +
                 ", lease time " + mLeaseTime;
     }
 
@@ -79,7 +79,7 @@ class DhcpAckPacket extends DhcpPacket {
         }
 
         addTlv(buffer, DHCP_SUBNET_MASK, mSubnetMask);
-        addTlv(buffer, DHCP_ROUTER, mGateway);
+        addTlv(buffer, DHCP_ROUTER, mGateways);
         addTlv(buffer, DHCP_DOMAIN_NAME, mDomainName);
         addTlv(buffer, DHCP_BROADCAST_ADDRESS, mBroadcastAddress);
         addTlv(buffer, DHCP_DNS_SERVER, mDnsServers);

diff --git a/services/net/java/android/net/dhcp/DhcpOfferPacket.java b/services/net/java/android/net/dhcp/DhcpOfferPacket.java
index 7ca7100..99154ef 100644 (file)
--- a/services/net/java/android/net/dhcp/DhcpOfferPacket.java
+++ b/services/net/java/android/net/dhcp/DhcpOfferPacket.java
@@ -48,7 +48,7 @@ class DhcpOfferPacket extends DhcpPacket {
         }
 
         return s + " OFFER, ip " + mYourIp + ", mask " + mSubnetMask +
-                dnsServers + ", gateway " + mGateway +
+                dnsServers + ", gateways " + mGateways +
                 " lease time " + mLeaseTime + ", domain " + mDomainName;
     }
 
@@ -81,7 +81,7 @@ class DhcpOfferPacket extends DhcpPacket {
         }
 
         addTlv(buffer, DHCP_SUBNET_MASK, mSubnetMask);
-        addTlv(buffer, DHCP_ROUTER, mGateway);
+        addTlv(buffer, DHCP_ROUTER, mGateways);
         addTlv(buffer, DHCP_DOMAIN_NAME, mDomainName);
         addTlv(buffer, DHCP_BROADCAST_ADDRESS, mBroadcastAddress);
         addTlv(buffer, DHCP_DNS_SERVER, mDnsServers);

diff --git a/services/net/java/android/net/dhcp/DhcpPacket.java b/services/net/java/android/net/dhcp/DhcpPacket.java
index d654089..8927bfa 100644 (file)
--- a/services/net/java/android/net/dhcp/DhcpPacket.java
+++ b/services/net/java/android/net/dhcp/DhcpPacket.java
@@ -128,7 +128,7 @@ abstract class DhcpPacket {
      * DHCP Optional Type: DHCP Router
      */
     protected static final byte DHCP_ROUTER = 3;
-    protected Inet4Address mGateway;
+    protected List <Inet4Address> mGateways;
 
     /**
      * DHCP Optional Type: DHCP DNS Server
@@ -706,8 +706,8 @@ abstract class DhcpPacket {
         Inet4Address nextIp;
         Inet4Address relayIp;
         byte[] clientMac;
-        List<Inet4Address> dnsServers = new ArrayList<Inet4Address>();
-        Inet4Address gateway = null; // aka router
+        List<Inet4Address> dnsServers = new ArrayList<>();
+        List<Inet4Address> gateways = new ArrayList<>();  // aka router
         Inet4Address serverIdentifier = null;
         Inet4Address netMask = null;
         String message = null;
@@ -883,8 +883,9 @@ abstract class DhcpPacket {
                             expectedLen = 4;
                             break;
                         case DHCP_ROUTER:
-                            gateway = readIpAddress(packet);
-                            expectedLen = 4;
+                            for (expectedLen = 0; expectedLen < optionLen; expectedLen += 4) {
+                                gateways.add(readIpAddress(packet));
+                            }
                             break;
                         case DHCP_DNS_SERVER:
                             for (expectedLen = 0; expectedLen < optionLen; expectedLen += 4) {
@@ -1020,7 +1021,7 @@ abstract class DhcpPacket {
         newPacket.mBroadcastAddress = bcAddr;
         newPacket.mDnsServers = dnsServers;
         newPacket.mDomainName = domainName;
-        newPacket.mGateway = gateway;
+        newPacket.mGateways = gateways;
         newPacket.mHostName = hostName;
         newPacket.mLeaseTime = leaseTime;
         newPacket.mMessage = message;
@@ -1076,7 +1077,11 @@ abstract class DhcpPacket {
         } catch (IllegalArgumentException e) {
             return null;
         }
-        results.gateway = mGateway;
+
+        if (mGateways.size() > 0) {
+            results.gateway = mGateways.get(0);
+        }
+
         results.dnsServers.addAll(mDnsServers);
         results.domains = mDomainName;
         results.serverAddress = mServerIdentifier;
@@ -1118,11 +1123,11 @@ abstract class DhcpPacket {
     public static ByteBuffer buildOfferPacket(int encap, int transactionId,
         boolean broadcast, Inet4Address serverIpAddr, Inet4Address clientIpAddr,
         byte[] mac, Integer timeout, Inet4Address netMask, Inet4Address bcAddr,
-        Inet4Address gateway, List<Inet4Address> dnsServers,
+        List<Inet4Address> gateways, List<Inet4Address> dnsServers,
         Inet4Address dhcpServerIdentifier, String domainName) {
         DhcpPacket pkt = new DhcpOfferPacket(
             transactionId, (short) 0, broadcast, serverIpAddr, INADDR_ANY, clientIpAddr, mac);
-        pkt.mGateway = gateway;
+        pkt.mGateways = gateways;
         pkt.mDnsServers = dnsServers;
         pkt.mLeaseTime = timeout;
         pkt.mDomainName = domainName;
@@ -1138,11 +1143,11 @@ abstract class DhcpPacket {
     public static ByteBuffer buildAckPacket(int encap, int transactionId,
         boolean broadcast, Inet4Address serverIpAddr, Inet4Address clientIpAddr,
         byte[] mac, Integer timeout, Inet4Address netMask, Inet4Address bcAddr,
-        Inet4Address gateway, List<Inet4Address> dnsServers,
+        List<Inet4Address> gateways, List<Inet4Address> dnsServers,
         Inet4Address dhcpServerIdentifier, String domainName) {
         DhcpPacket pkt = new DhcpAckPacket(
             transactionId, (short) 0, broadcast, serverIpAddr, INADDR_ANY, clientIpAddr, mac);
-        pkt.mGateway = gateway;
+        pkt.mGateways = gateways;
         pkt.mDnsServers = dnsServers;
         pkt.mLeaseTime = timeout;
         pkt.mDomainName = domainName;

diff --git a/services/tests/servicestests/src/android/net/dhcp/DhcpPacketTest.java b/services/tests/servicestests/src/android/net/dhcp/DhcpPacketTest.java
index 0f1cb88..7e60bf1 100644 (file)
--- a/services/tests/servicestests/src/android/net/dhcp/DhcpPacketTest.java
+++ b/services/tests/servicestests/src/android/net/dhcp/DhcpPacketTest.java
@@ -550,4 +550,38 @@ public class DhcpPacketTest extends TestCase {
                 "209.129.128.3,209.129.148.3,209.129.128.6",
                 "wvm.edu", "10.1.105.252", null, 86400, false, dhcpResults);
     }
+
+    @SmallTest
+    public void testMultipleRouters() throws Exception {
+        final ByteBuffer packet = ByteBuffer.wrap(HexEncoding.decode((
+            // Ethernet header.
+            "fc3d93000000" + "081735000000" + "0800" +
+            // IP header.
+            "45000148c2370000ff117ac2c0a8bd02ffffffff" +
+            // UDP header. TODO: fix invalid checksum (due to MAC address obfuscation).
+            "0043004401343beb" +
+            // BOOTP header.
+            "0201060027f518e20000800000000000c0a8bd310000000000000000" +
+            // MAC address.
+            "fc3d9300000000000000000000000000" +
+            // Server name.
+            "0000000000000000000000000000000000000000000000000000000000000000" +
+            "0000000000000000000000000000000000000000000000000000000000000000" +
+            // File.
+            "0000000000000000000000000000000000000000000000000000000000000000" +
+            "0000000000000000000000000000000000000000000000000000000000000000" +
+            "0000000000000000000000000000000000000000000000000000000000000000" +
+            "0000000000000000000000000000000000000000000000000000000000000000" +
+            // Options.
+            "638253633501023604c0abbd023304000070803a04000038403b04000062700104ffffff00" +
+            "0308c0a8bd01ffffff0006080808080808080404ff000000000000"
+        ).toCharArray(), false));
+
+        DhcpPacket offerPacket = DhcpPacket.decodeFullPacket(packet, ENCAP_L2);
+        assertTrue(offerPacket instanceof DhcpOfferPacket);
+        assertEquals("FC3D93000000", HexDump.toHexString(offerPacket.getClientMac()));
+        DhcpResults dhcpResults = offerPacket.toDhcpResults();
+        assertDhcpResults("192.168.189.49/24", "192.168.189.1", "8.8.8.8,8.8.4.4",
+                null, "192.171.189.2", null, 28800, false, dhcpResults);
+    }
 }