v4.19.13 snapshot.
diff --git a/samples/bpf/xdp2_kern.c b/samples/bpf/xdp2_kern.c
new file mode 100644
index 0000000..e012888
--- /dev/null
+++ b/samples/bpf/xdp2_kern.c
@@ -0,0 +1,114 @@
+/* Copyright (c) 2016 PLUMgrid
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of version 2 of the GNU General Public
+ * License as published by the Free Software Foundation.
+ */
+#define KBUILD_MODNAME "foo"
+#include <uapi/linux/bpf.h>
+#include <linux/in.h>
+#include <linux/if_ether.h>
+#include <linux/if_packet.h>
+#include <linux/if_vlan.h>
+#include <linux/ip.h>
+#include <linux/ipv6.h>
+#include "bpf_helpers.h"
+
+struct bpf_map_def SEC("maps") rxcnt = {
+ .type = BPF_MAP_TYPE_PERCPU_ARRAY,
+ .key_size = sizeof(u32),
+ .value_size = sizeof(long),
+ .max_entries = 256,
+};
+
+static void swap_src_dst_mac(void *data)
+{
+ unsigned short *p = data;
+ unsigned short dst[3];
+
+ dst[0] = p[0];
+ dst[1] = p[1];
+ dst[2] = p[2];
+ p[0] = p[3];
+ p[1] = p[4];
+ p[2] = p[5];
+ p[3] = dst[0];
+ p[4] = dst[1];
+ p[5] = dst[2];
+}
+
+static int parse_ipv4(void *data, u64 nh_off, void *data_end)
+{
+ struct iphdr *iph = data + nh_off;
+
+ if (iph + 1 > data_end)
+ return 0;
+ return iph->protocol;
+}
+
+static int parse_ipv6(void *data, u64 nh_off, void *data_end)
+{
+ struct ipv6hdr *ip6h = data + nh_off;
+
+ if (ip6h + 1 > data_end)
+ return 0;
+ return ip6h->nexthdr;
+}
+
+SEC("xdp1")
+int xdp_prog1(struct xdp_md *ctx)
+{
+ void *data_end = (void *)(long)ctx->data_end;
+ void *data = (void *)(long)ctx->data;
+ struct ethhdr *eth = data;
+ int rc = XDP_DROP;
+ long *value;
+ u16 h_proto;
+ u64 nh_off;
+ u32 ipproto;
+
+ nh_off = sizeof(*eth);
+ if (data + nh_off > data_end)
+ return rc;
+
+ h_proto = eth->h_proto;
+
+ if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
+ struct vlan_hdr *vhdr;
+
+ vhdr = data + nh_off;
+ nh_off += sizeof(struct vlan_hdr);
+ if (data + nh_off > data_end)
+ return rc;
+ h_proto = vhdr->h_vlan_encapsulated_proto;
+ }
+ if (h_proto == htons(ETH_P_8021Q) || h_proto == htons(ETH_P_8021AD)) {
+ struct vlan_hdr *vhdr;
+
+ vhdr = data + nh_off;
+ nh_off += sizeof(struct vlan_hdr);
+ if (data + nh_off > data_end)
+ return rc;
+ h_proto = vhdr->h_vlan_encapsulated_proto;
+ }
+
+ if (h_proto == htons(ETH_P_IP))
+ ipproto = parse_ipv4(data, nh_off, data_end);
+ else if (h_proto == htons(ETH_P_IPV6))
+ ipproto = parse_ipv6(data, nh_off, data_end);
+ else
+ ipproto = 0;
+
+ value = bpf_map_lookup_elem(&rxcnt, &ipproto);
+ if (value)
+ *value += 1;
+
+ if (ipproto == IPPROTO_UDP) {
+ swap_src_dst_mac(data);
+ rc = XDP_TX;
+ }
+
+ return rc;
+}
+
+char _license[] SEC("license") = "GPL";