af_packet: Add Queue mapping mode to af_packet fanout operation

This patch adds a queue mapping mode to the fanout operation of af_packet sockets. This allows user space af_packet users to better filter on flows ingressing and egressing via a specific hardware queue, and avoids the potential packet reordering that can occur when FANOUT_CPU is being used and irq affinity varies. Tested successfully by myself. applies to net-next Signed-off-by: Neil Horman <[email protected]> CC: "David S. Miller" <[email protected]> Signed-off-by: David S. Miller <[email protected]>
neviim · Jan 23, 2014 · 2d36097 · 2d36097
1 parent b414ac9
commit 2d36097
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Showing 2 changed files with 12 additions and 0 deletions.
diff --git a/include/uapi/linux/if_packet.h b/include/uapi/linux/if_packet.h
@@ -60,6 +60,7 @@ struct sockaddr_ll {
 #define PACKET_FANOUT_CPU		2
 #define PACKET_FANOUT_ROLLOVER		3
 #define PACKET_FANOUT_RND		4
+#define PACKET_FANOUT_QM		5
 #define PACKET_FANOUT_FLAG_ROLLOVER	0x1000
 #define PACKET_FANOUT_FLAG_DEFRAG	0x8000
 

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
@@ -1312,6 +1312,13 @@ static unsigned int fanout_demux_rollover(struct packet_fanout *f,
 	return idx;
 }
 
+static unsigned int fanout_demux_qm(struct packet_fanout *f,
+				    struct sk_buff *skb,
+				    unsigned int num)
+{
+	return skb_get_queue_mapping(skb) % num;
+}
+
 static bool fanout_has_flag(struct packet_fanout *f, u16 flag)
 {
 	return f->flags & (flag >> 8);
@@ -1351,6 +1358,9 @@ static int packet_rcv_fanout(struct sk_buff *skb, struct net_device *dev,
 	case PACKET_FANOUT_RND:
 		idx = fanout_demux_rnd(f, skb, num);
 		break;
+	case PACKET_FANOUT_QM:
+		idx = fanout_demux_qm(f, skb, num);
+		break;
 	case PACKET_FANOUT_ROLLOVER:
 		idx = fanout_demux_rollover(f, skb, 0, (unsigned int) -1, num);
 		break;
@@ -1421,6 +1431,7 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
 	case PACKET_FANOUT_LB:
 	case PACKET_FANOUT_CPU:
 	case PACKET_FANOUT_RND:
+	case PACKET_FANOUT_QM:
 		break;
 	default:
 		return -EINVAL;