packet: Add 'cpu' fanout policy.
David S. Miller [Wed, 6 Jul 2011 08:56:38 +0000 (01:56 -0700)]
Unfortunately we have to use a real modulus here as
the multiply trick won't work as effectively with cpu
numbers as it does with rxhash values.

Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/if_packet.h
net/packet/af_packet.c

index 84e684e..c148606 100644 (file)
@@ -53,6 +53,7 @@ struct sockaddr_ll {
 
 #define PACKET_FANOUT_HASH             0
 #define PACKET_FANOUT_LB               1
+#define PACKET_FANOUT_CPU              2
 #define PACKET_FANOUT_FLAG_DEFRAG      0x8000
 
 struct tpacket_stats {
index 7ba6871..41f0489 100644 (file)
@@ -447,6 +447,13 @@ static struct sock *fanout_demux_lb(struct packet_fanout *f, struct sk_buff *skb
        return f->arr[cur];
 }
 
+static struct sock *fanout_demux_cpu(struct packet_fanout *f, struct sk_buff *skb, unsigned int num)
+{
+       unsigned int cpu = smp_processor_id();
+
+       return f->arr[cpu % num];
+}
+
 static struct sk_buff *fanout_check_defrag(struct sk_buff *skb)
 {
        const struct iphdr *iph;
@@ -482,8 +489,8 @@ static struct sk_buff *fanout_check_defrag(struct sk_buff *skb)
        return skb;
 }
 
-static int packet_rcv_fanout_hash(struct sk_buff *skb, struct net_device *dev,
-                                 struct packet_type *pt, struct net_device *orig_dev)
+static int packet_rcv_fanout(struct sk_buff *skb, struct net_device *dev,
+                            struct packet_type *pt, struct net_device *orig_dev)
 {
        struct packet_fanout *f = pt->af_packet_priv;
        unsigned int num = f->num_members;
@@ -496,35 +503,25 @@ static int packet_rcv_fanout_hash(struct sk_buff *skb, struct net_device *dev,
                return 0;
        }
 
-       if (f->defrag) {
-               skb = fanout_check_defrag(skb);
-               if (!skb)
-                       return 0;
-       }
-
-       skb_get_rxhash(skb);
-
-       sk = fanout_demux_hash(f, skb, num);
-       po = pkt_sk(sk);
-
-       return po->prot_hook.func(skb, dev, &po->prot_hook, orig_dev);
-}
-
-static int packet_rcv_fanout_lb(struct sk_buff *skb, struct net_device *dev,
-                               struct packet_type *pt, struct net_device *orig_dev)
-{
-       struct packet_fanout *f = pt->af_packet_priv;
-       unsigned int num = f->num_members;
-       struct packet_sock *po;
-       struct sock *sk;
-
-       if (!net_eq(dev_net(dev), read_pnet(&f->net)) ||
-           !num) {
-               kfree_skb(skb);
-               return 0;
+       switch (f->type) {
+       case PACKET_FANOUT_HASH:
+       default:
+               if (f->defrag) {
+                       skb = fanout_check_defrag(skb);
+                       if (!skb)
+                               return 0;
+               }
+               skb_get_rxhash(skb);
+               sk = fanout_demux_hash(f, skb, num);
+               break;
+       case PACKET_FANOUT_LB:
+               sk = fanout_demux_lb(f, skb, num);
+               break;
+       case PACKET_FANOUT_CPU:
+               sk = fanout_demux_cpu(f, skb, num);
+               break;
        }
 
-       sk = fanout_demux_lb(f, skb, num);
        po = pkt_sk(sk);
 
        return po->prot_hook.func(skb, dev, &po->prot_hook, orig_dev);
@@ -571,6 +568,7 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
        switch (type) {
        case PACKET_FANOUT_HASH:
        case PACKET_FANOUT_LB:
+       case PACKET_FANOUT_CPU:
                break;
        default:
                return -EINVAL;
@@ -606,14 +604,7 @@ static int fanout_add(struct sock *sk, u16 id, u16 type_flags)
                        atomic_set(&match->sk_ref, 0);
                        match->prot_hook.type = po->prot_hook.type;
                        match->prot_hook.dev = po->prot_hook.dev;
-                       switch (type) {
-                       case PACKET_FANOUT_HASH:
-                               match->prot_hook.func = packet_rcv_fanout_hash;
-                               break;
-                       case PACKET_FANOUT_LB:
-                               match->prot_hook.func = packet_rcv_fanout_lb;
-                               break;
-                       }
+                       match->prot_hook.func = packet_rcv_fanout;
                        match->prot_hook.af_packet_priv = match;
                        dev_add_pack(&match->prot_hook);
                        list_add(&match->list, &fanout_list);