Add tagSocket/untagSocket NDK APIs

Provide native APIs to tag the various sockets used for network
transfer, which helps apps tracking down data usage inside their app.

We've had equivalent Java APIs since API level 14.
https://developer.android.com/reference/android/net/TrafficStats.html#tagSocket(java.net.Socket)
https://developer.android.com/reference/android/net/TrafficStats.html#untagSocket(java.net.Socket)

Given that the Java APIs implementation are in native side, providing
NDK directly will be easier for native users to use it.

Bug: 29761778
Bug: 202086915
Test: Tests in change Ic6554d9b98cef9b41b7eae06315d284c574c0a45
Change-Id: I884522be1dc40e8e959684442b3d736b5dcfdf5c

1 files changed, 55 insertions, 0 deletions

diff --git a/include/android/multinetwork.h b/include/android/multinetwork.h
index 509ee0e49b..4c83a14728 100644
--- a/include/android/multinetwork.h
+++ b/include/android/multinetwork.h
@@ -216,6 +216,61 @@ int android_res_nresult(int fd,
  */
 void android_res_cancel(int nsend_fd) __INTRODUCED_IN(29);
 
+/*
+ * Set the socket tag and owning UID for traffic statistics on the specified
+ * socket.
+ *
+ * Subsequent calls always replace any existing parameters. The socket tag and
+ * uid (if set) are kept when the socket is sent to another process using binder
+ * IPCs or other mechanisms such as UNIX socket fd passing. Any app can accept
+ * blame for future traffic performed on a socket originally created by another
+ * app by calling this method with its own UID (or calling
+ * android_tag_socket(int sockfd, int tag)). However, only apps holding the
+ * android.Manifest.permission#UPDATE_DEVICE_STATS permission may assign blame
+ * to another UIDs. If unset (default) the socket tag is 0, and the uid is the
+ * socket creator's uid.
+ *
+ * Returns 0 on success, or a negative POSIX error code (see errno.h) on
+ * failure.
+ *
+ * Available since API level 33.
+ */
+int android_tag_socket_with_uid(int sockfd, int tag, uid_t uid) __INTRODUCED_IN(33);
+
+/*
+ * Set the socket tag for traffic statistics on the specified socket.
+ *
+ * This function tags the socket with the caller's UID (accepting blame for
+ * future traffic performed on this socket) even if the socket was originally
+ * opened by another UID or was previously tagged by another UID. Subsequent
+ * calls always replace any existing parameters. The socket tag is kept when the
+ * socket is sent to another process using binder IPCs or other mechanisms such
+ * as UNIX socket fd passing.
+ *
+ * Returns 0 on success, or a negative POSIX error code (see errno.h) on
+ * failure.
+ *
+ * Available since API level 33.
+ */
+int android_tag_socket(int sockfd, int tag) __INTRODUCED_IN(33);
+
+/*
+ * Untag a network socket.
+ *
+ * Future traffic on this socket will no longer be associated with any
+ * previously configured tag and uid. If the socket was created by another UID
+ * or was previously tagged by another UID, calling this function will clear the
+ * statistics parameters, and thus the UID blamed for traffic on the socket will
+ * be the UID that originally created the socket, even if the socket was
+ * subsequently tagged by a different UID.
+ *
+ * Returns 0 on success, or a negative POSIX error code (see errno.h) on
+ * failure.
+ *
+ * Available since API level 33.
+ */
+int android_untag_socket(int sockfd) __INTRODUCED_IN(33);
+
 __END_DECLS
 
 #endif  // ANDROID_MULTINETWORK_H