multinetwork API: native implementation

Bug: 19537384
Change-Id: I04f4a7de2b1e583989b67a853df6ab50289c2185

api/current.txt

@@ -17153,6 +17153,7 @@ package android.net {
     method public int describeContents();
     method public java.net.InetAddress[] getAllByName(java.lang.String) throws java.net.UnknownHostException;
     method public java.net.InetAddress getByName(java.lang.String) throws java.net.UnknownHostException;
+    method public long getNetworkHandle();
     method public javax.net.SocketFactory getSocketFactory();
     method public java.net.URLConnection openConnection(java.net.URL) throws java.io.IOException;
     method public java.net.URLConnection openConnection(java.net.URL, java.net.Proxy) throws java.io.IOException;

api/system-current.txt

@@ -18414,6 +18414,7 @@ package android.net {
     method public int describeContents();
     method public java.net.InetAddress[] getAllByName(java.lang.String) throws java.net.UnknownHostException;
     method public java.net.InetAddress getByName(java.lang.String) throws java.net.UnknownHostException;
+    method public long getNetworkHandle();
     method public javax.net.SocketFactory getSocketFactory();
     method public java.net.URLConnection openConnection(java.net.URL) throws java.io.IOException;
     method public java.net.URLConnection openConnection(java.net.URL, java.net.Proxy) throws java.io.IOException;

core/java/android/net/Network.java

@@ -340,6 +340,35 @@ public class Network implements Parcelable {
         }
     }
 
+    /**
+     * Returns a handle representing this {@code Network}, for use with the NDK API.
+     */
+    public long getNetworkHandle() {
+        // The network handle is explicitly not the same as the netId.
+        //
+        // The netId is an implementation detail which might be changed in the
+        // future, or which alone (i.e. in the absence of some additional
+        // context) might not be sufficient to fully identify a Network.
+        //
+        // As such, the intention is to prevent accidental misuse of the API
+        // that might result if a developer assumed that handles and netIds
+        // were identical and passing a netId to a call expecting a handle
+        // "just worked".  Such accidental misuse, if widely deployed, might
+        // prevent future changes to the semantics of the netId field or
+        // inhibit the expansion of state required for Network objects.
+        //
+        // This extra layer of indirection might be seen as paranoia, and might
+        // never end up being necessary, but the added complexity is trivial.
+        // At some future date it may be desirable to realign the handle with
+        // Multiple Provisioning Domains API recommendations, as made by the
+        // IETF mif working group.
+        //
+        // The HANDLE_MAGIC value MUST be kept in sync with the corresponding
+        // value in the native/android/net.c NDK implementation.
+        final long HANDLE_MAGIC = 0xfacade;
+        return (((long) netId) << 32) | HANDLE_MAGIC;
+    }
+
     // implement the Parcelable interface
     public int describeContents() {
         return 0;

native/android/Android.mk

@@ -12,9 +12,10 @@ LOCAL_SRC_FILES:= \
     looper.cpp \
     native_activity.cpp \
     native_window.cpp \
+    net.c \
     obb.cpp \
     sensor.cpp \
-    storage_manager.cpp
+    storage_manager.cpp \
 
 LOCAL_SHARED_LIBRARIES := \
     liblog \
@@ -25,14 +26,17 @@ LOCAL_SHARED_LIBRARIES := \
     libbinder \
     libui \
     libgui \
-    libandroid_runtime
+    libandroid_runtime \
+    libnetd_client \
 
 LOCAL_STATIC_LIBRARIES := \
     libstorage
 
 LOCAL_C_INCLUDES += \
     frameworks/base/native/include \
-    frameworks/base/core/jni/android
+    frameworks/base/core/jni/android \
+    bionic/libc/dns/include \
+    system/netd/include \
 
 LOCAL_MODULE:= libandroid
 

native/android/net.c

@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+
+#include <android/multinetwork.h>
+#include <errno.h>
+#include <NetdClient.h>    // the functions that communicate with netd
+#include <resolv_netid.h>  // android_getaddrinfofornet()
+#include <stdlib.h>
+#include <sys/limits.h>
+
+
+static int getnetidfromhandle(net_handle_t handle, unsigned *netid) {
+    static const uint32_t k32BitMask = 0xffffffff;
+    // This value MUST be kept in sync with the corresponding value in
+    // the android.net.Network#getNetworkHandle() implementation.
+    static const uint32_t kHandleMagic = 0xfacade;
+
+    // Check for minimum acceptable version of the API in the low bits.
+    if (handle != NETWORK_UNSPECIFIED &&
+        (handle & k32BitMask) != kHandleMagic) {
+        return 0;
+    }
+
+    if (netid != NULL) {
+        *netid = ((handle >> (CHAR_BIT * sizeof(k32BitMask))) & k32BitMask);
+    }
+    return 1;
+}
+
+
+int android_setsocknetwork(net_handle_t network, int fd) {
+    unsigned netid;
+    if (!getnetidfromhandle(network, &netid)) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    int rval = setNetworkForSocket(netid, fd);
+    if (rval < 0) {
+        errno = -rval;
+        rval = -1;
+    }
+    return rval;
+}
+
+int android_setprocnetwork(net_handle_t network) {
+    unsigned netid;
+    if (!getnetidfromhandle(network, &netid)) {
+        errno = EINVAL;
+        return -1;
+    }
+
+    int rval = setNetworkForProcess(netid);
+    if (rval < 0) {
+        errno = -rval;
+        rval = -1;
+    }
+    return rval;
+}
+
+int android_getaddrinfofornetwork(net_handle_t network,
+        const char *node, const char *service,
+        const struct addrinfo *hints, struct addrinfo **res) {
+    unsigned netid;
+    if (!getnetidfromhandle(network, &netid)) {
+        errno = EINVAL;
+        return EAI_SYSTEM;
+    }
+
+    return android_getaddrinfofornet(node, service, hints, netid, 0, res);
+}