DHCP: Add a native method for making a DHCP socket. (566e0cb6) · Commits · e / os / android_frameworks_base

core/java/android/net/NetworkUtils.java

+7 −0

Original line number	Original line	Diff line number	Diff line
	@@ -16,9 +16,11 @@

	package android.net;		package android.net;

			import java.io.FileDescriptor;
	import java.net.InetAddress;		import java.net.InetAddress;
	import java.net.Inet4Address;		import java.net.Inet4Address;
	import java.net.Inet6Address;		import java.net.Inet6Address;
			import java.net.SocketException;
	import java.net.UnknownHostException;		import java.net.UnknownHostException;
	import java.util.Collection;		import java.util.Collection;
	import java.util.Locale;		import java.util.Locale;
	@@ -138,6 +140,11 @@ public class NetworkUtils {
	*/		*/
	public native static String getDhcpError();		public native static String getDhcpError();

			/**
			* Attaches a socket filter that accepts DHCP packets to the given socket.
			*/
			public native static void attachDhcpFilter(FileDescriptor fd) throws SocketException;

	/**		/**
	* Binds the current process to the network designated by {@code netId}. All sockets created		* Binds the current process to the network designated by {@code netId}. All sockets created
	* in the future (and not explicitly bound via a bound {@link SocketFactory} (see		* in the future (and not explicitly bound via a bound {@link SocketFactory} (see

core/jni/android_net_NetUtils.cpp

+50 −0

Original line number	Original line	Diff line number	Diff line
	@@ -24,6 +24,14 @@
	#include <android_runtime/AndroidRuntime.h>		#include <android_runtime/AndroidRuntime.h>
	#include <utils/Log.h>		#include <utils/Log.h>
	#include <arpa/inet.h>		#include <arpa/inet.h>
			#include <net/if.h>
			#include <linux/filter.h>
			#include <linux/if.h>
			#include <linux/if_ether.h>
			#include <linux/if_packet.h>
			#include <net/if_ether.h>
			#include <netinet/ip.h>
			#include <netinet/udp.h>
	#include <cutils/properties.h>		#include <cutils/properties.h>

	extern "C" {		extern "C" {
	@@ -53,6 +61,8 @@ char *dhcp_get_errmsg();

	namespace android {		namespace android {

			static const uint16_t kDhcpClientPort = 68;

	/*		/*
	* The following remembers the jfieldID's of the fields		* The following remembers the jfieldID's of the fields
	* of the DhcpInfo Java object, so that we don't have		* of the DhcpInfo Java object, so that we don't have
	@@ -215,6 +225,44 @@ static jstring android_net_utils_getDhcpError(JNIEnv* env, jobject clazz)
	return env->NewStringUTF(::dhcp_get_errmsg());		return env->NewStringUTF(::dhcp_get_errmsg());
	}		}

			static void android_net_utils_attachDhcpFilter(JNIEnv *env, jobject clazz, jobject javaFd)
			{
			int fd = jniGetFDFromFileDescriptor(env, javaFd);
			uint32_t ip_offset = sizeof(ether_header);
			uint32_t proto_offset = ip_offset + offsetof(iphdr, protocol);
			uint32_t flags_offset = ip_offset + offsetof(iphdr, frag_off);
			uint32_t dport_indirect_offset = ip_offset + offsetof(udphdr, dest);
			struct sock_filter filter_code[] = {
			// Check the protocol is UDP.
			BPF_STMT(BPF_LD \| BPF_B \| BPF_ABS, proto_offset),
			BPF_JUMP(BPF_JMP \| BPF_JEQ \| BPF_K, IPPROTO_UDP, 0, 6),

			// Check this is not a fragment.
			BPF_STMT(BPF_LD \| BPF_H \| BPF_ABS, flags_offset),
			BPF_JUMP(BPF_JMP \| BPF_JSET \| BPF_K, 0x1fff, 4, 0),

			// Get the IP header length.
			BPF_STMT(BPF_LDX \| BPF_B \| BPF_MSH, ip_offset),

			// Check the destination port.
			BPF_STMT(BPF_LD \| BPF_H \| BPF_IND, dport_indirect_offset),
			BPF_JUMP(BPF_JMP \| BPF_JEQ \| BPF_K, kDhcpClientPort, 0, 1),

			// Accept or reject.
			BPF_STMT(BPF_RET \| BPF_K, 0xffff),
			BPF_STMT(BPF_RET \| BPF_K, 0)
			};
			struct sock_fprog filter = {
			sizeof(filter_code) / sizeof(filter_code[0]),
			filter_code,
			};

			if (setsockopt(fd, SOL_SOCKET, SO_ATTACH_FILTER, &filter, sizeof(filter)) != 0) {
			jniThrowExceptionFmt(env, "java/net/SocketException",
			"setsockopt(SO_ATTACH_FILTER): %s", strerror(errno));
			}
			}

	static jboolean android_net_utils_bindProcessToNetwork(JNIEnv *env, jobject thiz, jint netId)		static jboolean android_net_utils_bindProcessToNetwork(JNIEnv *env, jobject thiz, jint netId)
	{		{
	return (jboolean) !setNetworkForProcess(netId);		return (jboolean) !setNetworkForProcess(netId);
	@@ -242,6 +290,7 @@ static jboolean android_net_utils_protectFromVpn(JNIEnv *env, jobject thiz, jint
	return (jboolean) !protectFromVpn(socket);		return (jboolean) !protectFromVpn(socket);
	}		}


	// ----------------------------------------------------------------------------		// ----------------------------------------------------------------------------

	/*		/*
	@@ -261,6 +310,7 @@ static JNINativeMethod gNetworkUtilMethods[] = {
	{ "bindProcessToNetworkForHostResolution", "(I)Z", (void*) android_net_utils_bindProcessToNetworkForHostResolution },		{ "bindProcessToNetworkForHostResolution", "(I)Z", (void*) android_net_utils_bindProcessToNetworkForHostResolution },
	{ "bindSocketToNetwork", "(II)I", (void*) android_net_utils_bindSocketToNetwork },		{ "bindSocketToNetwork", "(II)I", (void*) android_net_utils_bindSocketToNetwork },
	{ "protectFromVpn", "(I)Z", (void*)android_net_utils_protectFromVpn },		{ "protectFromVpn", "(I)Z", (void*)android_net_utils_protectFromVpn },
			{ "attachDhcpFilter", "(Ljava/io/FileDescriptor;)V", (void*) android_net_utils_attachDhcpFilter },
	};		};

	int register_android_net_NetworkUtils(JNIEnv* env)		int register_android_net_NetworkUtils(JNIEnv* env)