samples: bpf: Convert xdp_redirect_map_kern.o to XDP samples helper

Also update it to use consistent SEC("xdp") and SEC("xdp_devmap")
naming, and use global variable instead of BPF map for copying the mac
address.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-20-memxor@gmail.com

1 files changed, 95 insertions, 0 deletions

diff --git a/samples/bpf/xdp_redirect_map.bpf.c b/samples/bpf/xdp_redirect_map.bpf.c
new file mode 100644
index 000000000000..59efd656e1b2
--- /dev/null
+++ b/samples/bpf/xdp_redirect_map.bpf.c
@@ -0,0 +1,95 @@
+/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+#define KBUILD_MODNAME "foo"
+
+#include "vmlinux.h"
+#include "xdp_sample.bpf.h"
+#include "xdp_sample_shared.h"
+
+/* The 2nd xdp prog on egress does not support skb mode, so we define two
+ * maps, tx_port_general and tx_port_native.
+ */
+struct {
+	__uint(type, BPF_MAP_TYPE_DEVMAP);
+	__uint(key_size, sizeof(int));
+	__uint(value_size, sizeof(int));
+	__uint(max_entries, 1);
+} tx_port_general SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_DEVMAP);
+	__uint(key_size, sizeof(int));
+	__uint(value_size, sizeof(struct bpf_devmap_val));
+	__uint(max_entries, 1);
+} tx_port_native SEC(".maps");
+
+/* store egress interface mac address */
+const volatile char tx_mac_addr[ETH_ALEN];
+
+static __always_inline int xdp_redirect_map(struct xdp_md *ctx, void *redirect_map)
+{
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data = (void *)(long)ctx->data;
+	u32 key = bpf_get_smp_processor_id();
+	struct ethhdr *eth = data;
+	struct datarec *rec;
+	u64 nh_off;
+
+	nh_off = sizeof(*eth);
+	if (data + nh_off > data_end)
+		return XDP_DROP;
+
+	rec = bpf_map_lookup_elem(&rx_cnt, &key);
+	if (!rec)
+		return XDP_PASS;
+	NO_TEAR_INC(rec->processed);
+	swap_src_dst_mac(data);
+	return bpf_redirect_map(redirect_map, 0, 0);
+}
+
+SEC("xdp")
+int xdp_redirect_map_general(struct xdp_md *ctx)
+{
+	return xdp_redirect_map(ctx, &tx_port_general);
+}
+
+SEC("xdp")
+int xdp_redirect_map_native(struct xdp_md *ctx)
+{
+	return xdp_redirect_map(ctx, &tx_port_native);
+}
+
+SEC("xdp_devmap/egress")
+int xdp_redirect_map_egress(struct xdp_md *ctx)
+{
+	void *data_end = (void *)(long)ctx->data_end;
+	void *data = (void *)(long)ctx->data;
+	struct ethhdr *eth = data;
+	u64 nh_off;
+
+	nh_off = sizeof(*eth);
+	if (data + nh_off > data_end)
+		return XDP_DROP;
+
+	__builtin_memcpy(eth->h_source, (const char *)tx_mac_addr, ETH_ALEN);
+
+	return XDP_PASS;
+}
+
+/* Redirect require an XDP bpf_prog loaded on the TX device */
+SEC("xdp")
+int xdp_redirect_dummy_prog(struct xdp_md *ctx)
+{
+	return XDP_PASS;
+}
+
+char _license[] SEC("license") = "GPL";