Commit a29b3ca1 authored by Kumar Kartikeya Dwivedi's avatar Kumar Kartikeya Dwivedi Committed by Alexei Starovoitov
Browse files

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: default avatarKumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210821002010.845777-22-memxor@gmail.com
parent bbe65865

samples/bpf/Makefile

+4 −3
Original line number Diff line number Diff line
@@ -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

samples/bpf/xdp_redirect_map_multi_kern.c→samples/bpf/xdp_redirect_map_multi.bpf.c

+22 −28
Original line number Diff line number Diff line 
// 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;