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samples: bpf: Convert xdp_redirect_map_multi_kern.o to XDP samples he…
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…lper

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 <[email protected]>
Signed-off-by: Alexei Starovoitov <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
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kkdwivedi authored and Alexei Starovoitov committed Aug 24, 2021
1 parent bbe6586 commit a29b3ca
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Showing 2 changed files with 26 additions and 31 deletions.
7 changes: 4 additions & 3 deletions samples/bpf/Makefile
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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
Expand All @@ -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
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Original file line number Diff line number Diff line change
@@ -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);
Expand All @@ -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;
Expand Down

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