Extend to receive NFLOG packets.

Packets captured and logged by the NFLOG target are unicast, so
extend to catch and decode them.  To avoid escaping issues, the raw
contents are passed around as hex strings.

Bug: 18335678
Change-Id: Ib7299500baa00080a1f000f9da843eb527363353

1 files changed, 17 insertions, 9 deletions

diff --git a/libcutils/uevent.c b/libcutils/uevent.c
index 97a81e3..827170a 100644
--- a/libcutils/uevent.c
+++ b/libcutils/uevent.c
@@ -31,12 +31,12 @@
  */
 ssize_t uevent_kernel_multicast_recv(int socket, void *buffer, size_t length)
 {
-    uid_t user = -1;
-    return uevent_kernel_multicast_uid_recv(socket, buffer, length, &user);
+    uid_t uid = -1;
+    return uevent_kernel_multicast_uid_recv(socket, buffer, length, &uid);
 }
 
 /**
- * Like the above, but passes a uid_t in by reference. In the event that this
+ * Like the above, but passes a uid_t in by pointer. In the event that this
  * fails due to a bad uid check, the uid_t will be set to the uid of the
  * socket's peer.
  *
@@ -44,8 +44,12 @@ ssize_t uevent_kernel_multicast_recv(int socket, void *buffer, size_t length)
  * returns -1, sets errno to EIO, and sets "user" to the UID associated with the
  * message. If the peer UID cannot be determined, "user" is set to -1."
  */
-ssize_t uevent_kernel_multicast_uid_recv(int socket, void *buffer,
-                                         size_t length, uid_t *user)
+ssize_t uevent_kernel_multicast_uid_recv(int socket, void *buffer, size_t length, uid_t *uid)
+{
+    return uevent_kernel_recv(socket, buffer, length, true, uid);
+}
+
+ssize_t uevent_kernel_recv(int socket, void *buffer, size_t length, bool require_group, uid_t *uid)
 {
     struct iovec iov = { buffer, length };
     struct sockaddr_nl addr;
@@ -60,7 +64,7 @@ ssize_t uevent_kernel_multicast_uid_recv(int socket, void *buffer,
         0,
     };
 
-    *user = -1;
+    *uid = -1;
     ssize_t n = recvmsg(socket, &hdr, 0);
     if (n <= 0) {
         return n;
@@ -73,14 +77,18 @@ ssize_t uevent_kernel_multicast_uid_recv(int socket, void *buffer,
     }
 
     struct ucred *cred = (struct ucred *)CMSG_DATA(cmsg);
-    *user = cred->uid;
+    *uid = cred->uid;
     if (cred->uid != 0) {
         /* ignoring netlink message from non-root user */
         goto out;
     }
 
-    if (addr.nl_groups == 0 || addr.nl_pid != 0) {
-        /* ignoring non-kernel or unicast netlink message */
+    if (addr.nl_pid != 0) {
+        /* ignore non-kernel */
+        goto out;
+    }
+    if (require_group && addr.nl_groups == 0) {
+        /* ignore unicast messages when requested */
         goto out;
     }