Subject: [PATCH bpf-next 2/3] bpf: add BPF_PROG_TEST_RUN support for flow dissector

From: Stanislav Fomichev <[email-masked]>
Date: Tue, 22 Jan 2019 13:23:14 -0800

The input is packet data, the output is struct bpf_flow_key. This should
make it easy to test flow dissector programs without elaborate
setup.

Signed-off-by: Stanislav Fomichev <[email-masked]>
---
 include/linux/bpf.h |  3 ++
 net/bpf/test_run.c  | 75 ++++++++++++++++++++++++++++++++++++++++++++-
 net/core/filter.c   |  1 +
 3 files changed, 78 insertions(+), 1 deletion(-)

diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index e734f163bd0b..701ef954a258 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -397,6 +397,9 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
 			  union bpf_attr __user *uattr);
 int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
 			  union bpf_attr __user *uattr);
+int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
+				     const union bpf_attr *kattr,
+				     union bpf_attr __user *uattr);
 
 /* an array of programs to be executed under rcu_lock.
  *
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index fa2644d276ef..ecad72885f23 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -16,12 +16,26 @@
 static __always_inline u32 bpf_test_run_one(struct bpf_prog *prog, void *ctx,
 		struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE])
 {
+	struct bpf_skb_data_end *cb;
+	struct sk_buff *skb;
 	u32 ret;
 
 	preempt_disable();
 	rcu_read_lock();
 	bpf_cgroup_storage_set(storage);
-	ret = BPF_PROG_RUN(prog, ctx);
+
+	switch (prog->type) {
+	case BPF_PROG_TYPE_FLOW_DISSECTOR:
+		skb = (struct sk_buff *)ctx;
+		cb = (struct bpf_skb_data_end *)skb->cb;
+		ret = __skb_flow_bpf_dissect(prog, ctx, &flow_keys_dissector,
+					     cb->qdisc_cb.flow_keys);
+		break;
+	default:
+		ret = BPF_PROG_RUN(prog, ctx);
+		break;
+	}
+
 	rcu_read_unlock();
 	preempt_enable();
 
@@ -240,3 +254,62 @@ int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
 	kfree(data);
 	return ret;
 }
+
+int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
+				     const union bpf_attr *kattr,
+				     union bpf_attr __user *uattr)
+{
+	u32 size = kattr->test.data_size_in;
+	u32 repeat = kattr->test.repeat;
+	struct bpf_flow_keys flow_keys;
+	struct bpf_skb_data_end *cb;
+	u32 retval, duration;
+	struct sk_buff *skb;
+	struct sock *sk;
+	void *data;
+	int ret;
+
+	if (prog->type != BPF_PROG_TYPE_FLOW_DISSECTOR)
+		return -EINVAL;
+
+	data = bpf_test_init(kattr, size, NET_SKB_PAD + NET_IP_ALIGN,
+			     SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	sk = kzalloc(sizeof(*sk), GFP_USER);
+	if (!sk) {
+		kfree(data);
+		return -ENOMEM;
+	}
+	sock_net_set(sk, current->nsproxy->net_ns);
+	sock_init_data(NULL, sk);
+
+	skb = build_skb(data, 0);
+	if (!skb) {
+		kfree(data);
+		kfree(sk);
+		return -ENOMEM;
+	}
+	skb->sk = sk;
+
+	skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
+	__skb_put(skb, size);
+	skb->protocol = eth_type_trans(skb,
+				       current->nsproxy->net_ns->loopback_dev);
+	skb_reset_network_header(skb);
+
+	cb = (struct bpf_skb_data_end *)skb->cb;
+	cb->qdisc_cb.flow_keys = &flow_keys;
+	ret = bpf_test_run(prog, skb, repeat, &retval, &duration);
+	if (ret)
+		goto out;
+
+	ret = bpf_test_finish(kattr, uattr, &flow_keys, sizeof(flow_keys),
+			      retval, duration);
+
+out:
+	kfree_skb(skb);
+	kfree(sk);
+	return ret;
+}
diff --git a/net/core/filter.c b/net/core/filter.c
index 2b3b436ef545..ff4641dae2be 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -7690,6 +7690,7 @@ const struct bpf_verifier_ops flow_dissector_verifier_ops = {
 };
 
 const struct bpf_prog_ops flow_dissector_prog_ops = {
+	.test_run		= bpf_prog_test_run_flow_dissector,
 };
 
 int sk_detach_filter(struct sock *sk)
-- 
2.20.1.321.g9e740568ce-goog