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Commit 61da29a9 authored by Alexander Wuerstlein's avatar Alexander Wuerstlein
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Ensure DHCP requests have nonempty hostnames 

If the net.hostname property is empty or not found, Android issues
DHCP requests with an empty hostname field (option 12). RFC2132 section
3.14 prescribes a minimum length of 1 byte for the hostname.

To fix this, a generic 'android-dhcp' hostname is used as a fallback.

Change-Id: I7a92e7295f72b3255e4fba6498fb4039906eb702
parent 5587ea46

services/net/java/android/net/dhcp/DhcpPacket.java

+6 −1
Original line number Diff line number Diff line
@@ -602,7 +602,12 @@ abstract class DhcpPacket { 
    protected void addCommonClientTlvs(ByteBuffer buf) {

        addTlv(buf, DHCP_MAX_MESSAGE_SIZE, (short) MAX_LENGTH);

        addTlv(buf, DHCP_VENDOR_CLASS_ID, "android-dhcp-" + Build.VERSION.RELEASE);

        addTlv(buf, DHCP_HOST_NAME, SystemProperties.get("net.hostname"));



        /* the default 'android-dhcp' is there to make sure the hostname is

         * never empty, because the DHCP standard forbids it (RFC2132, section

         * 3.14) and certain DHCP forwarders and servers ignore such malformed

         * requests */

        addTlv(buf, DHCP_HOST_NAME, SystemProperties.get("net.hostname", "android-dhcp"));

    }



    /**