1 files changed, 50 insertions, 0 deletions

diff --git a/net/can/raw.c b/net/can/raw.c
index 63ffdb0..31b9748 100644
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -74,6 +74,12 @@ MODULE_ALIAS("can-proto-1");
  * storing the single filter in dfilter, to avoid using dynamic memory.
  */
 
+struct uniqframe {
+	ktime_t tstamp;
+	const struct sk_buff *skb;
+	unsigned int join_rx_count;
+};
+
 struct raw_sock {
 	struct sock sk;
 	int bound;
@@ -82,10 +88,12 @@ struct raw_sock {
 	int loopback;
 	int recv_own_msgs;
 	int fd_frames;
+	int join_filters;
 	int count;                 /* number of active filters */
 	struct can_filter dfilter; /* default/single filter */
 	struct can_filter *filter; /* pointer to filter(s) */
 	can_err_mask_t err_mask;
+	struct uniqframe __percpu *uniq;
 };
 
 /*
@@ -123,6 +131,26 @@ static void raw_rcv(struct sk_buff *oskb, void *data)
 	if (!ro->fd_frames && oskb->len != CAN_MTU)
 		return;
 
+	/* eliminate multiple filter matches for the same skb */
+	if (this_cpu_ptr(ro->uniq)->skb == oskb &&
+	    ktime_equal(this_cpu_ptr(ro->uniq)->tstamp, oskb->tstamp)) {
+		if (ro->join_filters) {
+			this_cpu_inc(ro->uniq->join_rx_count);
+			/* drop frame until all enabled filters matched */
+			if (this_cpu_ptr(ro->uniq)->join_rx_count < ro->count)
+				return;
+		} else {
+			return;
+		}
+	} else {
+		this_cpu_ptr(ro->uniq)->skb = oskb;
+		this_cpu_ptr(ro->uniq)->tstamp = oskb->tstamp;
+		this_cpu_ptr(ro->uniq)->join_rx_count = 1;
+		/* drop first frame to check all enabled filters? */
+		if (ro->join_filters && ro->count > 1)
+			return;
+	}
+
 	/* clone the given skb to be able to enqueue it into the rcv queue */
 	skb = skb_clone(oskb, GFP_ATOMIC);
 	if (!skb)
@@ -296,6 +324,12 @@ static int raw_init(struct sock *sk)
 	ro->loopback         = 1;
 	ro->recv_own_msgs    = 0;
 	ro->fd_frames        = 0;
+	ro->join_filters     = 0;
+
+	/* alloc_percpu provides zero'ed memory */
+	ro->uniq = alloc_percpu(struct uniqframe);
+	if (unlikely(!ro->uniq))
+		return -ENOMEM;
 
 	/* set notifier */
 	ro->notifier.notifier_call = raw_notifier;
@@ -339,6 +373,7 @@ static int raw_release(struct socket *sock)
 	ro->ifindex = 0;
 	ro->bound   = 0;
 	ro->count   = 0;
+	free_percpu(ro->uniq);
 
 	sock_orphan(sk);
 	sock->sk = NULL;
@@ -583,6 +618,15 @@ static int raw_setsockopt(struct socket *sock, int level, int optname,
 
 		break;
 
+	case CAN_RAW_JOIN_FILTERS:
+		if (optlen != sizeof(ro->join_filters))
+			return -EINVAL;
+
+		if (copy_from_user(&ro->join_filters, optval, optlen))
+			return -EFAULT;
+
+		break;
+
 	default:
 		return -ENOPROTOOPT;
 	}
@@ -647,6 +691,12 @@ static int raw_getsockopt(struct socket *sock, int level, int optname,
 		val = &ro->fd_frames;
 		break;
 
+	case CAN_RAW_JOIN_FILTERS:
+		if (len > sizeof(int))
+			len = sizeof(int);
+		val = &ro->join_filters;
+		break;
+
 	default:
 		return -ENOPROTOOPT;
 	}