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

samples/bpf/Makefile

@@ -163,7 +163,6 @@ always-y += tcp_clamp_kern.o
 always-y += tcp_basertt_kern.o
 always-y += tcp_tos_reflect_kern.o
 always-y += tcp_dumpstats_kern.o
-always-y += xdp_redirect_map_kern.o
 always-y += xdp_redirect_map_multi_kern.o
 always-y += xdp_rxq_info_kern.o
 always-y += xdp2skb_meta_kern.o
@@ -357,6 +356,7 @@ endef
 CLANG_SYS_INCLUDES = $(call get_sys_includes,$(CLANG))
 
 $(obj)/xdp_redirect_cpu.bpf.o: $(obj)/xdp_sample.bpf.o
+$(obj)/xdp_redirect_map.bpf.o: $(obj)/xdp_sample.bpf.o
 $(obj)/xdp_redirect.bpf.o: $(obj)/xdp_sample.bpf.o
 $(obj)/xdp_monitor.bpf.o: $(obj)/xdp_sample.bpf.o
 
@@ -368,10 +368,12 @@ $(obj)/%.bpf.o: $(src)/%.bpf.c $(obj)/vmlinux.h $(src)/xdp_sample.bpf.h $(src)/x
 		-I$(srctree)/tools/lib $(CLANG_SYS_INCLUDES) \
 		-c $(filter %.bpf.c,$^) -o $@
 
-LINKED_SKELS := xdp_redirect_cpu.skel.h xdp_redirect.skel.h xdp_monitor.skel.h
+LINKED_SKELS := xdp_redirect_cpu.skel.h xdp_redirect_map.skel.h \
+		 xdp_redirect.skel.h xdp_monitor.skel.h
 clean-files += $(LINKED_SKELS)
 
 xdp_redirect_cpu.skel.h-deps := xdp_redirect_cpu.bpf.o xdp_sample.bpf.o
+xdp_redirect_map.skel.h-deps := xdp_redirect_map.bpf.o xdp_sample.bpf.o
 xdp_redirect.skel.h-deps := xdp_redirect.bpf.o xdp_sample.bpf.o
 xdp_monitor.skel.h-deps := xdp_monitor.bpf.o xdp_sample.bpf.o
 

samples/bpf/xdp_redirect_map.bpf.c

@@ -10,14 +10,10 @@
  * General Public License for more details.
  */
 #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/bpf_helpers.h>
+
+#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.
@@ -26,114 +22,71 @@ struct {
 	__uint(type, BPF_MAP_TYPE_DEVMAP);
 	__uint(key_size, sizeof(int));
 	__uint(value_size, sizeof(int));
-	__uint(max_entries, 100);
+	__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, 100);
+	__uint(max_entries, 1);
 } tx_port_native SEC(".maps");
 
-/* Count RX packets, as XDP bpf_prog doesn't get direct TX-success
- * feedback.  Redirect TX errors can be caught via a tracepoint.
- */
-struct {
-	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
-	__type(key, u32);
-	__type(value, long);
-	__uint(max_entries, 1);
-} rxcnt SEC(".maps");
-
-/* map to store egress interface mac address */
-struct {
-	__uint(type, BPF_MAP_TYPE_ARRAY);
-	__type(key, u32);
-	__type(value, __be64);
-	__uint(max_entries, 1);
-} tx_mac SEC(".maps");
-
-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];
-}
+/* 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;
-	int rc = XDP_DROP;
-	long *value;
-	u32 key = 0;
-	u64 nh_off;
-	int vport;
-
-	nh_off = sizeof(*eth);
-	if (data + nh_off > data_end)
-		return rc;
-
-	/* constant virtual port */
-	vport = 0;
-
-	/* count packet in global counter */
-	value = bpf_map_lookup_elem(&rxcnt, &key);
-	if (value)
-		*value += 1;
-
-	swap_src_dst_mac(data);
-
-	/* send packet out physical port */
-	return bpf_redirect_map(redirect_map, vport, 0);
-}
-
-SEC("xdp_redirect_general")
-int xdp_redirect_map_general(struct xdp_md *ctx)
-{
-	return xdp_redirect_map(ctx, &tx_port_general);
-}
-
-SEC("xdp_redirect_native")
-int xdp_redirect_map_native(struct xdp_md *ctx)
-{
-	return xdp_redirect_map(ctx, &tx_port_native);
-}
-
-SEC("xdp_devmap/map_prog")
-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;
-	__be64 *mac;
-	u32 key = 0;
+	struct datarec *rec;
 	u64 nh_off;
 
 	nh_off = sizeof(*eth);
 	if (data + nh_off > data_end)
 		return XDP_DROP;
 
-	mac = bpf_map_lookup_elem(&tx_mac, &key);
-	if (mac)
-		__builtin_memcpy(eth->h_source, mac, ETH_ALEN);
+	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_redirect_dummy")
+SEC("xdp")
 int xdp_redirect_dummy_prog(struct xdp_md *ctx)
 {
 	return XDP_PASS;