net: packet: add randomized fanout scheduler
We currently allow for different fanout scheduling policies in pf_packet
such as scheduling by skb's rxhash, round-robin, by cpu, and rollover.
Also allow for a random, equidistributed selection of the socket from the
fanout process group.
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 1fdf9ab..bee9bfd 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -88,7 +88,7 @@
#include <linux/virtio_net.h>
#include <linux/errqueue.h>
#include <linux/net_tstamp.h>
-
+#include <linux/reciprocal_div.h>
#ifdef CONFIG_INET
#include <net/inet_common.h>
#endif
@@ -1158,6 +1158,13 @@
return smp_processor_id() % num;
}
+static unsigned int fanout_demux_rnd(struct packet_fanout *f,
+ struct sk_buff *skb,
+ unsigned int num)
+{
+ return reciprocal_divide(prandom_u32(), num);
+}
+
static unsigned int fanout_demux_rollover(struct packet_fanout *f,
struct sk_buff *skb,
unsigned int idx, unsigned int skip,
@@ -1215,6 +1222,9 @@
case PACKET_FANOUT_CPU:
idx = fanout_demux_cpu(f, skb, num);
break;
+ case PACKET_FANOUT_RND:
+ idx = fanout_demux_rnd(f, skb, num);
+ break;
case PACKET_FANOUT_ROLLOVER:
idx = fanout_demux_rollover(f, skb, 0, (unsigned int) -1, num);
break;
@@ -1284,6 +1294,7 @@
case PACKET_FANOUT_HASH:
case PACKET_FANOUT_LB:
case PACKET_FANOUT_CPU:
+ case PACKET_FANOUT_RND:
break;
default:
return -EINVAL;