1 files changed, 90 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_lwt_redirect.c b/tools/testing/selftests/bpf/progs/test_lwt_redirect.c
new file mode 100644
index 000000000000..8c895122f293
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_lwt_redirect.c
@@ -0,0 +1,90 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_endian.h>
+#include <bpf/bpf_helpers.h>
+#include <linux/ip.h>
+#include "bpf_tracing_net.h"
+
+/* We don't care about whether the packet can be received by network stack.
+ * Just care if the packet is sent to the correct device at correct direction
+ * and not panic the kernel.
+ */
+static int prepend_dummy_mac(struct __sk_buff *skb)
+{
+	char mac[] = {0x1, 0x2, 0x3, 0x4, 0x5, 0x6, 0xf,
+		      0xe, 0xd, 0xc, 0xb, 0xa, 0x08, 0x00};
+
+	if (bpf_skb_change_head(skb, ETH_HLEN, 0))
+		return -1;
+
+	if (bpf_skb_store_bytes(skb, 0, mac, sizeof(mac), 0))
+		return -1;
+
+	return 0;
+}
+
+/* Use the last byte of IP address to redirect the packet */
+static int get_redirect_target(struct __sk_buff *skb)
+{
+	struct iphdr *iph = NULL;
+	void *start = (void *)(long)skb->data;
+	void *end = (void *)(long)skb->data_end;
+
+	if (start + sizeof(*iph) > end)
+		return -1;
+
+	iph = (struct iphdr *)start;
+	return bpf_ntohl(iph->daddr) & 0xff;
+}
+
+SEC("redir_ingress")
+int test_lwt_redirect_in(struct __sk_buff *skb)
+{
+	int target = get_redirect_target(skb);
+
+	if (target < 0)
+		return BPF_OK;
+
+	if (prepend_dummy_mac(skb))
+		return BPF_DROP;
+
+	return bpf_redirect(target, BPF_F_INGRESS);
+}
+
+SEC("redir_egress")
+int test_lwt_redirect_out(struct __sk_buff *skb)
+{
+	int target = get_redirect_target(skb);
+
+	if (target < 0)
+		return BPF_OK;
+
+	if (prepend_dummy_mac(skb))
+		return BPF_DROP;
+
+	return bpf_redirect(target, 0);
+}
+
+SEC("redir_egress_nomac")
+int test_lwt_redirect_out_nomac(struct __sk_buff *skb)
+{
+	int target = get_redirect_target(skb);
+
+	if (target < 0)
+		return BPF_OK;
+
+	return bpf_redirect(target, 0);
+}
+
+SEC("redir_ingress_nomac")
+int test_lwt_redirect_in_nomac(struct __sk_buff *skb)
+{
+	int target = get_redirect_target(skb);
+
+	if (target < 0)
+		return BPF_OK;
+
+	return bpf_redirect(target, BPF_F_INGRESS);
+}
+
+char _license[] SEC("license") = "GPL";