netdev - [PATCH bpf-next v4 21/22] samples: bpf: Convert xdp_redirect_map_multi

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Date:   Sat, 21 Aug 2021 05:50:09 +0530
From:   Kumar Kartikeya Dwivedi <memxor@...il.com>
To:     bpf@...r.kernel.org
Cc:     Kumar Kartikeya Dwivedi <memxor@...il.com>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>,
        Jesper Dangaard Brouer <brouer@...hat.com>,
        Toke Høiland-Jørgensen <toke@...hat.com>,
        netdev@...r.kernel.org
Subject: [PATCH bpf-next v4 21/22] samples: bpf: Convert xdp_redirect_map_multi_kern.o to XDP samples helper

One of the notable changes is using a BPF_MAP_TYPE_HASH instead of array
map to store mac addresses of devices, as the resizing behavior was
based on max_ifindex, which unecessarily maximized the capacity of map
beyond what was needed.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@...il.com>
---
 samples/bpf/Makefile                          |  7 +--
 ...ti_kern.c => xdp_redirect_map_multi.bpf.c} | 50 ++++++++-----------
 2 files changed, 26 insertions(+), 31 deletions(-)
 rename samples/bpf/{xdp_redirect_map_multi_kern.c => xdp_redirect_map_multi.bpf.c} (64%)

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 6decc8f9bcc2..2b3d9e39c4f3 100644
--- a/samples/bpf/Makefile
+++ b/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_multi_kern.o
 always-y += xdp_rxq_info_kern.o
 always-y += xdp2skb_meta_kern.o
 always-y += syscall_tp_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_multi.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
@@ -369,11 +369,12 @@ $(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_map.skel.h \
-		 xdp_redirect.skel.h xdp_monitor.skel.h
+LINKED_SKELS := xdp_redirect_cpu.skel.h xdp_redirect_map_multi.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_multi.skel.h-deps := xdp_redirect_map_multi.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
diff --git a/samples/bpf/xdp_redirect_map_multi_kern.c b/samples/bpf/xdp_redirect_map_multi.bpf.c
similarity index 64%
rename from samples/bpf/xdp_redirect_map_multi_kern.c
rename to samples/bpf/xdp_redirect_map_multi.bpf.c
index 71aa23d1cb2b..8f59d430cb64 100644
--- a/samples/bpf/xdp_redirect_map_multi_kern.c
+++ b/samples/bpf/xdp_redirect_map_multi.bpf.c
@@ -1,11 +1,14 @@
 // SPDX-License-Identifier: GPL-2.0
 #define KBUILD_MODNAME "foo"
-#include <uapi/linux/bpf.h>
-#include <linux/in.h>
-#include <linux/if_ether.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"
+
+enum {
+	BPF_F_BROADCAST		= (1ULL << 3),
+	BPF_F_EXCLUDE_INGRESS	= (1ULL << 4),
+};
 
 struct {
 	__uint(type, BPF_MAP_TYPE_DEVMAP_HASH);
@@ -21,50 +24,41 @@ struct {
 	__uint(max_entries, 32);
 } forward_map_native SEC(".maps");
 
+/* map to store egress interfaces mac addresses */
 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 interfaces mac addresses, set the
- * max_entries to 1 and extend it in user sapce prog.
- */
-struct {
-	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(type, BPF_MAP_TYPE_HASH);
 	__type(key, u32);
 	__type(value, __be64);
-	__uint(max_entries, 1);
+	__uint(max_entries, 32);
 } mac_map SEC(".maps");
 
 static int xdp_redirect_map(struct xdp_md *ctx, void *forward_map)
 {
-	long *value;
-	u32 key = 0;
+	u32 key = bpf_get_smp_processor_id();
+	struct datarec *rec;
 
-	/* count packet in global counter */
-	value = bpf_map_lookup_elem(&rxcnt, &key);
-	if (value)
-		*value += 1;
+	rec = bpf_map_lookup_elem(&rx_cnt, &key);
+	if (!rec)
+		return XDP_PASS;
+	NO_TEAR_INC(rec->processed);
 
-	return bpf_redirect_map(forward_map, key,
+	return bpf_redirect_map(forward_map, 0,
 				BPF_F_BROADCAST | BPF_F_EXCLUDE_INGRESS);
 }
 
-SEC("xdp_redirect_general")
+SEC("xdp")
 int xdp_redirect_map_general(struct xdp_md *ctx)
 {
 	return xdp_redirect_map(ctx, &forward_map_general);
 }
 
-SEC("xdp_redirect_native")
+SEC("xdp")
 int xdp_redirect_map_native(struct xdp_md *ctx)
 {
 	return xdp_redirect_map(ctx, &forward_map_native);
 }
 
-SEC("xdp_devmap/map_prog")
+SEC("xdp_devmap/egress")
 int xdp_devmap_prog(struct xdp_md *ctx)
 {
 	void *data_end = (void *)(long)ctx->data_end;
-- 
2.33.0