Hi Kui-Feng,
On 10/26/23 3:18 AM, Kui-Feng Lee wrote:
On 10/25/23 18:15, Kui-Feng Lee wrote:
On 10/25/23 15:09, Martin KaFai Lau wrote:
On 10/25/23 2:24 PM, Kui-Feng Lee wrote:
On 10/24/23 14:48, Daniel Borkmann wrote:
This work adds a new, minimal BPF-programmable device called "netkit"
(former PoC code-name "meta") we recently presented at LSF/MM/BPF. The
core idea is that BPF programs are executed within the drivers xmit routine
and therefore e.g. in case of containers/Pods moving BPF processing closer
to the source.
Sorry for intruding into this discussion! Although it is too late to
mentioned this since this patchset have been v4 already.
I notice netkit has introduced a new attach type. I wonder if it
possible to implement it as a new struct_ops type.
Could your elaborate more about what does this struct_ops type do and how is it different from the SCHED_CLS bpf prog that the netkit is running?
I found the code has been landed.
Basing on the landed code and
the patchset of registering bpf struct_ops from modules that I
am working on, it will looks like what is done in following patch.
No changes on syscall, uapi and libbpf are required.
diff --git a/drivers/net/netkit.c b/drivers/net/netkit.c
index 7e484f9fd3ae..e4eafaf397bf 100644
--- a/drivers/net/netkit.c
+++ b/drivers/net/netkit.c
@@ -20,6 +20,7 @@ struct netkit {
struct bpf_mprog_entry __rcu *active;
enum netkit_action policy;
struct bpf_mprog_bundle bundle;
+ struct hlist_head ops_list;
/* Needed in slow-path */
enum netkit_mode mode;
@@ -27,6 +28,13 @@ struct netkit {
u32 headroom;
};
+struct netkit_ops {
+ struct hlist_node node;
+ int ifindex;
+
+ int (*xmit)(struct sk_buff *skb);
+};
+
struct netkit_link {
struct bpf_link link;
struct net_device *dev;
@@ -46,6 +54,22 @@ netkit_run(const struct bpf_mprog_entry *entry, struct sk_buff *skb,
if (ret != NETKIT_NEXT)
break;
}
+
+ return ret;
+}
+
+static __always_inline int
+netkit_run_st_ops(const struct netkit *nk, struct sk_buff *skb,
+ enum netkit_action ret)
+{
+ struct netkit_ops *ops;
+
+ hlist_for_each_entry_rcu(ops, &nk->ops_list, node) {
+ ret = ops->xmit(skb);
+ if (ret != NETKIT_NEXT)
+ break;
+ }
+
return ret;
}
@@ -80,6 +104,8 @@ static netdev_tx_t netkit_xmit(struct sk_buff *skb, struct net_device *dev)
entry = rcu_dereference(nk->active);
if (entry)
ret = netkit_run(entry, skb, ret);
+ if (ret == NETKIT_NEXT)
+ ret = netkit_run_st_ops(nk, skb, ret);
switch (ret) {
case NETKIT_NEXT:
case NETKIT_PASS:
I don't think it makes sense to cramp struct ops in here for what has been
solved already with the bpf_mprog interface in a more efficient way and with
control dependencies for the insertion (before/after relative programs/links).
The latter is in particular crucial for a multi-user interface when dealing
with network traffic (think for example: policy, forwarder, observability
prog, etc).
Thanks,
Daniel
