LineageOS/android_packages_modules_Connectivity
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

DHCP: Add a native method for making a DHCP socket.

Browse Source 
Bug: 19704592
Change-Id: Iadd60d39c93aaabd2917e76791101a7d313b34be
This commit is contained in:
Lorenzo Colitti
2015-03-06 19:57:39 +09:00
parent e82e0f0a8c
commit c70fbac892
2 changed files with 57 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
core/java/android/net/NetworkUtils.java
View File

@@ -16,9 +16,11 @@
package android.net;
import java.io.FileDescriptor;
import java.net.InetAddress;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.SocketException;
import java.net.UnknownHostException;
import java.util.Collection;
import java.util.Locale;
@@ -138,6 +140,11 @@ public class NetworkUtils {
*/
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
* in the future (and not explicitly bound via a bound {@link SocketFactory} (see

50
core/jni/android_net_NetUtils.cpp
View File

@@ -24,6 +24,14 @@
#include <android_runtime/AndroidRuntime.h>
#include <utils/Log.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>
extern "C" {
@@ -53,6 +61,8 @@ char *dhcp_get_errmsg();
namespace android {
static const uint16_t kDhcpClientPort = 68;
/*
* The following remembers the jfieldID's of the fields
* 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());
}
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)
{
return (jboolean) !setNetworkForProcess(netId);
@@ -242,6 +290,7 @@ static jboolean android_net_utils_protectFromVpn(JNIEnv *env, jobject thiz, jint
return (jboolean) !protectFromVpn(socket);
}
// ----------------------------------------------------------------------------
/*
@@ -261,6 +310,7 @@ static JNINativeMethod gNetworkUtilMethods[] = {
{ "bindProcessToNetworkForHostResolution", "(I)Z", (void*) android_net_utils_bindProcessToNetworkForHostResolution },
{ "bindSocketToNetwork", "(II)I", (void*) android_net_utils_bindSocketToNetwork },
{ "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)