commit e84b833609c7b1676002047a5705fafadb669ae8
author yuanyunli <yuanyunli@vivo.corp-partner.google.com> Wed Jan 09 16:59:37 2019 +0800
committer Lorenzo Colitti <lorenzo@google.com> Mon Apr 29 10:54:28 2019 +0900
tree d1c23639ddbda214dd28a4c84fd9f73bbcc25987
parent 1cff26a70710259aeb9f998c9b3740a6cd2f7f17

Parse the server host name field of the dhcp package

Some hotspot devices will fill in the server host name field of the DHCP
package, such as iphone. Parsing the server host name of the DHCP
package can help identify ios hotspots.

Bug: 120584519
Test: 127423755
Test: builds, boots, wifi works
Change-Id: I8c5a7dc8ab117f062f9401f58832edada321436b
Merged-In: I60071bc029d25485bf204cfd3a8cebd538ca12b6
(cherry picked from commit 43f1bc9d5399e1d659bb5e7ac08dc31d36345d5f)

core/java/android/net/DhcpResults.java

diff --git a/core/java/android/net/DhcpResults.java b/core/java/android/net/DhcpResults.java
index 2e52f72..97be51a 100644
--- a/core/java/android/net/DhcpResults.java
+++ b/core/java/android/net/DhcpResults.java
@@ -64,6 +64,8 @@
     @UnsupportedAppUsage
     public int mtu;
 
+    public String serverHostName;
+
     public DhcpResults() {
         super();
     }
@@ -97,6 +99,7 @@
             vendorInfo = source.vendorInfo;
             leaseDuration = source.leaseDuration;
             mtu = source.mtu;
+            serverHostName = source.serverHostName;
         }
     }
 
@@ -129,6 +132,7 @@
         vendorInfo = null;
         leaseDuration = 0;
         mtu = 0;
+        serverHostName = null;
     }
 
     @Override
@@ -139,6 +143,7 @@
         str.append(" Vendor info ").append(vendorInfo);
         str.append(" lease ").append(leaseDuration).append(" seconds");
         if (mtu != 0) str.append(" MTU ").append(mtu);
+        str.append(" Servername ").append(serverHostName);
 
         return str.toString();
     }
@@ -154,6 +159,7 @@
         return toStaticIpConfiguration().equals(target.toStaticIpConfiguration())
                 && Objects.equals(serverAddress, target.serverAddress)
                 && Objects.equals(vendorInfo, target.vendorInfo)
+                && Objects.equals(serverHostName, target.serverHostName)
                 && leaseDuration == target.leaseDuration
                 && mtu == target.mtu;
     }
@@ -179,6 +185,7 @@
         dest.writeInt(mtu);
         InetAddressUtils.parcelInetAddress(dest, serverAddress, flags);
         dest.writeString(vendorInfo);
+        dest.writeString(serverHostName);
     }
 
     @Override
@@ -193,6 +200,7 @@
         dhcpResults.mtu = in.readInt();
         dhcpResults.serverAddress = (Inet4Address) InetAddressUtils.unparcelInetAddress(in);
         dhcpResults.vendorInfo = in.readString();
+        dhcpResults.serverHostName = in.readString();
         return dhcpResults;
     }
 

packages/NetworkStack/src/android/net/dhcp/DhcpPacket.java

diff --git a/packages/NetworkStack/src/android/net/dhcp/DhcpPacket.java b/packages/NetworkStack/src/android/net/dhcp/DhcpPacket.java
index d7ff98b1..c5b75f8 100644
--- a/packages/NetworkStack/src/android/net/dhcp/DhcpPacket.java
+++ b/packages/NetworkStack/src/android/net/dhcp/DhcpPacket.java
@@ -309,6 +309,11 @@
     protected final byte[] mClientMac;
 
     /**
+     * The server host name from server.
+     */
+    protected String mServerHostName;
+
+    /**
      * Asks the packet object to create a ByteBuffer serialization of
      * the packet for transmission.
      */
@@ -848,6 +853,7 @@
         Inet4Address ipDst = null;
         Inet4Address bcAddr = null;
         Inet4Address requestedIp = null;
+        String serverHostName = null;
 
         // The following are all unsigned integers. Internally we store them as signed integers of
         // the same length because that way we're guaranteed that they can't be out of the range of
@@ -989,9 +995,9 @@
         packet.get(clientMac);
 
         // skip over address padding (16 octets allocated)
-        packet.position(packet.position() + (16 - addrLen)
-                        + 64    // skip server host name (64 chars)
-                        + 128); // skip boot file name (128 chars)
+        packet.position(packet.position() + (16 - addrLen));
+        serverHostName = readAsciiString(packet, 64, false);
+        packet.position(packet.position() + 128);
 
         // Ensure this is a DHCP packet with a magic cookie, and not BOOTP. http://b/31850211
         if (packet.remaining() < 4) {
@@ -1192,6 +1198,7 @@
         newPacket.mT2 = T2;
         newPacket.mVendorId = vendorId;
         newPacket.mVendorInfo = vendorInfo;
+        newPacket.mServerHostName = serverHostName;
         return newPacket;
     }
 
@@ -1251,6 +1258,7 @@
         results.vendorInfo = mVendorInfo;
         results.leaseDuration = (mLeaseTime != null) ? mLeaseTime : INFINITE_LEASE;
         results.mtu = (mMtu != null && MIN_MTU <= mMtu && mMtu <= MAX_MTU) ? mMtu : 0;
+        results.serverHostName = mServerHostName;
 
         return results;
     }