1 files changed, 116 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_do_redirect.c b/tools/testing/selftests/bpf/progs/test_xdp_do_redirect.c
new file mode 100644
index 000000000000..3abf068b8446
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_xdp_do_redirect.c
@@ -0,0 +1,116 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+
+#define ETH_ALEN 6
+#define HDR_SZ (sizeof(struct ethhdr) + sizeof(struct ipv6hdr) + sizeof(struct udphdr))
+
+/**
+ * enum frame_mark - magics to distinguish page/packet paths
+ * @MARK_XMIT: page was recycled due to the frame being "xmitted" by the NIC.
+ * @MARK_IN: frame is being processed by the input XDP prog.
+ * @MARK_SKB: frame did hit the TC ingress hook as an skb.
+ */
+enum frame_mark {
+	MARK_XMIT	= 0U,
+	MARK_IN		= 0x42,
+	MARK_SKB	= 0x45,
+};
+
+const volatile int ifindex_out;
+const volatile int ifindex_in;
+const volatile __u8 expect_dst[ETH_ALEN];
+volatile int pkts_seen_xdp = 0;
+volatile int pkts_seen_zero = 0;
+volatile int pkts_seen_tc = 0;
+volatile int retcode = XDP_REDIRECT;
+
+SEC("xdp")
+int xdp_redirect(struct xdp_md *xdp)
+{
+	__u32 *metadata = (void *)(long)xdp->data_meta;
+	void *data_end = (void *)(long)xdp->data_end;
+	void *data = (void *)(long)xdp->data;
+
+	__u8 *payload = data + HDR_SZ;
+	int ret = retcode;
+
+	if (payload + 1 > data_end)
+		return XDP_ABORTED;
+
+	if (xdp->ingress_ifindex != (__u32)ifindex_in)
+		return XDP_ABORTED;
+
+	if (metadata + 1 > data)
+		return XDP_ABORTED;
+
+	if (*metadata != 0x42)
+		return XDP_ABORTED;
+
+	if (*payload == MARK_XMIT)
+		pkts_seen_zero++;
+
+	*payload = MARK_IN;
+
+	if (bpf_xdp_adjust_meta(xdp, sizeof(__u64)))
+		return XDP_ABORTED;
+
+	if (retcode > XDP_PASS)
+		retcode--;
+
+	if (ret == XDP_REDIRECT)
+		return bpf_redirect(ifindex_out, 0);
+
+	return ret;
+}
+
+static bool check_pkt(void *data, void *data_end, const __u32 mark)
+{
+	struct ipv6hdr *iph = data + sizeof(struct ethhdr);
+	__u8 *payload = data + HDR_SZ;
+
+	if (payload + 1 > data_end)
+		return false;
+
+	if (iph->nexthdr != IPPROTO_UDP || *payload != MARK_IN)
+		return false;
+
+	/* reset the payload so the same packet doesn't get counted twice when
+	 * it cycles back through the kernel path and out the dst veth
+	 */
+	*payload = mark;
+	return true;
+}
+
+SEC("xdp")
+int xdp_count_pkts(struct xdp_md *xdp)
+{
+	void *data = (void *)(long)xdp->data;
+	void *data_end = (void *)(long)xdp->data_end;
+
+	if (check_pkt(data, data_end, MARK_XMIT))
+		pkts_seen_xdp++;
+
+	/* Return %XDP_DROP to recycle the data page with %MARK_XMIT, like
+	 * it exited a physical NIC. Those pages will be counted in the
+	 * pkts_seen_zero counter above.
+	 */
+	return XDP_DROP;
+}
+
+SEC("tc")
+int tc_count_pkts(struct __sk_buff *skb)
+{
+	void *data = (void *)(long)skb->data;
+	void *data_end = (void *)(long)skb->data_end;
+
+	if (check_pkt(data, data_end, MARK_SKB))
+		pkts_seen_tc++;
+
+	/* Will be either recycled or freed, %MARK_SKB makes sure it won't
+	 * hit any of the counters above.
+	 */
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";