bpf: add bpf_redirect() helper
Existing bpf_clone_redirect() helper clones skb before redirecting
it to RX or TX of destination netdev.
Introduce bpf_redirect() helper that does that without cloning.
Benchmarked with two hosts using 10G ixgbe NICs.
One host is doing line rate pktgen.
Another host is configured as:
$ tc qdisc add dev $dev ingress
$ tc filter add dev $dev root pref 10 u32 match u32 0 0 flowid 1:2 \
action bpf run object-file tcbpf1_kern.o section clone_redirect_xmit drop
so it receives the packet on $dev and immediately xmits it on $dev + 1
The section 'clone_redirect_xmit' in tcbpf1_kern.o file has the program
that does bpf_clone_redirect() and performance is 2.0 Mpps
$ tc filter add dev $dev root pref 10 u32 match u32 0 0 flowid 1:2 \
action bpf run object-file tcbpf1_kern.o section redirect_xmit drop
which is using bpf_redirect() - 2.4 Mpps
and using cls_bpf with integrated actions as:
$ tc filter add dev $dev root pref 10 \
bpf run object-file tcbpf1_kern.o section redirect_xmit integ_act classid 1
performance is 2.5 Mpps
To summarize:
u32+act_bpf using clone_redirect - 2.0 Mpps
u32+act_bpf using redirect - 2.4 Mpps
cls_bpf using redirect - 2.5 Mpps
For comparison linux bridge in this setup is doing 2.1 Mpps
and ixgbe rx + drop in ip_rcv - 7.8 Mpps
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/core/dev.c b/net/core/dev.c
index 00dccfa..ee0d628 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3670,6 +3670,14 @@
case TC_ACT_QUEUED:
kfree_skb(skb);
return NULL;
+ case TC_ACT_REDIRECT:
+ /* skb_mac_header check was done by cls/act_bpf, so
+ * we can safely push the L2 header back before
+ * redirecting to another netdev
+ */
+ __skb_push(skb, skb->mac_len);
+ skb_do_redirect(skb);
+ return NULL;
default:
break;
}
diff --git a/net/core/filter.c b/net/core/filter.c
index 971d6ba..da3f3d9 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -1427,6 +1427,48 @@
.arg3_type = ARG_ANYTHING,
};
+struct redirect_info {
+ u32 ifindex;
+ u32 flags;
+};
+
+static DEFINE_PER_CPU(struct redirect_info, redirect_info);
+static u64 bpf_redirect(u64 ifindex, u64 flags, u64 r3, u64 r4, u64 r5)
+{
+ struct redirect_info *ri = this_cpu_ptr(&redirect_info);
+
+ ri->ifindex = ifindex;
+ ri->flags = flags;
+ return TC_ACT_REDIRECT;
+}
+
+int skb_do_redirect(struct sk_buff *skb)
+{
+ struct redirect_info *ri = this_cpu_ptr(&redirect_info);
+ struct net_device *dev;
+
+ dev = dev_get_by_index_rcu(dev_net(skb->dev), ri->ifindex);
+ ri->ifindex = 0;
+ if (unlikely(!dev)) {
+ kfree_skb(skb);
+ return -EINVAL;
+ }
+
+ if (BPF_IS_REDIRECT_INGRESS(ri->flags))
+ return dev_forward_skb(dev, skb);
+
+ skb->dev = dev;
+ return dev_queue_xmit(skb);
+}
+
+const struct bpf_func_proto bpf_redirect_proto = {
+ .func = bpf_redirect,
+ .gpl_only = false,
+ .ret_type = RET_INTEGER,
+ .arg1_type = ARG_ANYTHING,
+ .arg2_type = ARG_ANYTHING,
+};
+
static u64 bpf_get_cgroup_classid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
{
return task_get_classid((struct sk_buff *) (unsigned long) r1);
@@ -1607,6 +1649,8 @@
return &bpf_skb_get_tunnel_key_proto;
case BPF_FUNC_skb_set_tunnel_key:
return bpf_get_skb_set_tunnel_key_proto();
+ case BPF_FUNC_redirect:
+ return &bpf_redirect_proto;
default:
return sk_filter_func_proto(func_id);
}
