From: Cong Wang <cong.wang@xxxxxxxxxxxxx>
Introduce a kfunc, bpf_skb_tc_classify(), to reuse exising TC filters
on *any* Qdisc to classify the skb.
Signed-off-by: Cong Wang <cong.wang@xxxxxxxxxxxxx>
Co-developed-by: Amery Hung <amery.hung@xxxxxxxxxxxxx>
Signed-off-by: Amery Hung <amery.hung@xxxxxxxxxxxxx>
---
net/sched/sch_bpf.c | 68 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 68 insertions(+)
diff --git a/net/sched/sch_bpf.c b/net/sched/sch_bpf.c
index b0e7c3a19c30..1910a58a3352 100644
--- a/net/sched/sch_bpf.c
+++ b/net/sched/sch_bpf.c
@@ -571,6 +571,73 @@ __bpf_kfunc void bpf_qdisc_set_skb_dequeue(struct sk_buff *skb)
__this_cpu_write(bpf_skb_dequeue, skb);
}
+/* bpf_skb_tc_classify - Classify an skb using an existing filter referred
+ * to by the specified handle on the net device of index ifindex.
+ * @skb: The skb to be classified.
+ * @handle: The handle of the filter to be referenced.
+ * @ifindex: The ifindex of the net device where the filter is attached.
+ *
+ * Returns a 64-bit integer containing the tc action verdict and the classid,
+ * created as classid << 32 | action.
+ */
+__bpf_kfunc u64 bpf_skb_tc_classify(struct sk_buff *skb, int ifindex,
+ u32 handle)
+{
+ struct net *net = dev_net(skb->dev);
+ const struct Qdisc_class_ops *cops;
+ struct tcf_result res = {};
+ struct tcf_block *block;
+ struct tcf_chain *chain;
+ struct net_device *dev;
+ int result = TC_ACT_OK;
+ unsigned long cl = 0;
+ struct Qdisc *q;
+
+ rcu_read_lock();
+ dev = dev_get_by_index_rcu(net, ifindex);
+ if (!dev)
+ goto out;
+ q = qdisc_lookup_rcu(dev, handle);
+ if (!q)
+ goto out;
+
+ cops = q->ops->cl_ops;
+ if (!cops)
+ goto out;
+ if (!cops->tcf_block)
+ goto out;
+ if (TC_H_MIN(handle)) {
+ cl = cops->find(q, handle);
+ if (cl == 0)
+ goto out;
+ }
+ block = cops->tcf_block(q, cl, NULL);
+ if (!block)
+ goto out;
+
+ for (chain = tcf_get_next_chain(block, NULL);
+ chain;
+ chain = tcf_get_next_chain(block, chain)) {
+ struct tcf_proto *tp;
+
+ result = tcf_classify(skb, NULL, tp, &res, false);
+ if (result >= 0) {
+ switch (result) {
+ case TC_ACT_QUEUED:
+ case TC_ACT_STOLEN:
+ case TC_ACT_TRAP:
+ fallthrough;
+ case TC_ACT_SHOT:
+ rcu_read_unlock();
+ return result;
+ }
+ }
+ }
+out:
+ rcu_read_unlock();
+ return (res.class << 32 | result);
+}
+
__diag_pop();
BTF_SET8_START(skb_kfunc_btf_ids)
@@ -578,6 +645,7 @@ BTF_ID_FLAGS(func, bpf_skb_acquire, KF_ACQUIRE)
BTF_ID_FLAGS(func, bpf_skb_release, KF_RELEASE)
BTF_ID_FLAGS(func, bpf_skb_get_hash)
BTF_ID_FLAGS(func, bpf_qdisc_set_skb_dequeue, KF_RELEASE)
+BTF_ID_FLAGS(func, bpf_skb_tc_classify)
BTF_SET8_END(skb_kfunc_btf_ids)
static const struct btf_kfunc_id_set skb_kfunc_set = {
--
2.20.1
