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Commit f74599f7 authored by Thomas Graf's avatar Thomas Graf Committed by David S. Miller
Browse files

bpf: Add tests and samples for LWT-BPF 



Adds a series of tests to verify the functionality of attaching
BPF programs at LWT hooks.

Also adds a sample which collects a histogram of packet sizes which
pass through an LWT hook.

$ ./lwt_len_hist.sh
Starting netserver with host 'IN(6)ADDR_ANY' port '12865' and family AF_UNSPEC
MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 192.168.253.2 () port 0 AF_INET : demo
Recv   Send    Send
Socket Socket  Message  Elapsed
Size   Size    Size     Time     Throughput
bytes  bytes   bytes    secs.    10^6bits/sec

 87380  16384  16384    10.00    39857.69
       1 -> 1        : 0        |                                      |
       2 -> 3        : 0        |                                      |
       4 -> 7        : 0        |                                      |
       8 -> 15       : 0        |                                      |
      16 -> 31       : 0        |                                      |
      32 -> 63       : 22       |                                      |
      64 -> 127      : 98       |                                      |
     128 -> 255      : 213      |                                      |
     256 -> 511      : 1444251  |********                              |
     512 -> 1023     : 660610   |***                                   |
    1024 -> 2047     : 535241   |**                                    |
    2048 -> 4095     : 19       |                                      |
    4096 -> 8191     : 180      |                                      |
    8192 -> 16383    : 5578023  |************************************* |
   16384 -> 32767    : 632099   |***                                   |
   32768 -> 65535    : 6575     |                                      |

Signed-off-by: default avatarThomas Graf <tgraf@suug.ch>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 3a0af8fd

samples/bpf/Makefile

+4 −0
Original line number Diff line number Diff line
@@ -29,6 +29,7 @@ hostprogs-y += test_current_task_under_cgroup 
hostprogs-y += trace_event

hostprogs-y += sampleip

hostprogs-y += tc_l2_redirect

hostprogs-y += lwt_len_hist



test_lru_dist-objs := test_lru_dist.o libbpf.o

sock_example-objs := sock_example.o libbpf.o
@@ -59,6 +60,7 @@ test_current_task_under_cgroup-objs := bpf_load.o libbpf.o \ 
trace_event-objs := bpf_load.o libbpf.o trace_event_user.o

sampleip-objs := bpf_load.o libbpf.o sampleip_user.o

tc_l2_redirect-objs := bpf_load.o libbpf.o tc_l2_redirect_user.o

lwt_len_hist-objs := bpf_load.o libbpf.o lwt_len_hist_user.o



# Tell kbuild to always build the programs

always := $(hostprogs-y)
@@ -89,6 +91,7 @@ always += xdp2_kern.o 
always += test_current_task_under_cgroup_kern.o

always += trace_event_kern.o

always += sampleip_kern.o

always += lwt_len_hist_kern.o



HOSTCFLAGS += -I$(objtree)/usr/include

HOSTCFLAGS += -I$(srctree)/tools/testing/selftests/bpf/
@@ -117,6 +120,7 @@ HOSTLOADLIBES_test_current_task_under_cgroup += -lelf 
HOSTLOADLIBES_trace_event += -lelf

HOSTLOADLIBES_sampleip += -lelf

HOSTLOADLIBES_tc_l2_redirect += -l elf

HOSTLOADLIBES_lwt_len_hist += -l elf



# Allows pointing LLC/CLANG to a LLVM backend with bpf support, redefine on cmdline:

#  make samples/bpf/ LLC=~/git/llvm/build/bin/llc CLANG=~/git/llvm/build/bin/clang

samples/bpf/bpf_helpers.h

+4 −0
Original line number Diff line number Diff line
@@ -80,6 +80,8 @@ struct bpf_map_def { 
	unsigned int map_flags;

};



static int (*bpf_skb_load_bytes)(void *ctx, int off, void *to, int len) =

	(void *) BPF_FUNC_skb_load_bytes;

static int (*bpf_skb_store_bytes)(void *ctx, int off, void *from, int len, int flags) =

	(void *) BPF_FUNC_skb_store_bytes;

static int (*bpf_l3_csum_replace)(void *ctx, int off, int from, int to, int flags) =
@@ -88,6 +90,8 @@ static int (*bpf_l4_csum_replace)(void *ctx, int off, int from, int to, int flag 
	(void *) BPF_FUNC_l4_csum_replace;

static int (*bpf_skb_under_cgroup)(void *ctx, void *map, int index) =

	(void *) BPF_FUNC_skb_under_cgroup;

static int (*bpf_skb_change_head)(void *, int len, int flags) =

	(void *) BPF_FUNC_skb_change_head;



#if defined(__x86_64__)

samples/bpf/lwt_len_hist.sh

0 → 100644
+37 −0
Original line number Diff line number Diff line 
#!/bin/bash



NS1=lwt_ns1

VETH0=tst_lwt1a

VETH1=tst_lwt1b



TRACE_ROOT=/sys/kernel/debug/tracing



function cleanup {

	ip route del 192.168.253.2/32 dev $VETH0 2> /dev/null

	ip link del $VETH0 2> /dev/null

	ip link del $VETH1 2> /dev/null

	ip netns exec $NS1 killall netserver

	ip netns delete $NS1 2> /dev/null

}



cleanup



ip netns add $NS1

ip link add $VETH0 type veth peer name $VETH1

ip link set dev $VETH0 up

ip addr add 192.168.253.1/24 dev $VETH0

ip link set $VETH1 netns $NS1

ip netns exec $NS1 ip link set dev $VETH1 up

ip netns exec $NS1 ip addr add 192.168.253.2/24 dev $VETH1

ip netns exec $NS1 netserver



echo 1 > ${TRACE_ROOT}/tracing_on

cp /dev/null ${TRACE_ROOT}/trace

ip route add 192.168.253.2/32 encap bpf out obj lwt_len_hist_kern.o section len_hist dev $VETH0

netperf -H 192.168.253.2 -t TCP_STREAM

cat ${TRACE_ROOT}/trace | grep -v '^#'

./lwt_len_hist

cleanup

echo 0 > ${TRACE_ROOT}/tracing_on



exit 0

samples/bpf/lwt_len_hist_kern.c

0 → 100644
+82 −0
Original line number Diff line number Diff line 
/* Copyright (c) 2016 Thomas Graf <tgraf@tgraf.ch>

 *

 * 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.

 */



#include <uapi/linux/bpf.h>

#include <uapi/linux/if_ether.h>

#include <uapi/linux/ip.h>

#include <uapi/linux/in.h>

#include "bpf_helpers.h"



# define printk(fmt, ...)						\

		({							\

			char ____fmt[] = fmt;				\

			bpf_trace_printk(____fmt, sizeof(____fmt),	\

				     ##__VA_ARGS__);			\

		})



struct bpf_elf_map {

	__u32 type;

	__u32 size_key;

	__u32 size_value;

	__u32 max_elem;

	__u32 flags;

	__u32 id;

	__u32 pinning;

};



struct bpf_elf_map SEC("maps") lwt_len_hist_map = {

	.type = BPF_MAP_TYPE_PERCPU_HASH,

	.size_key = sizeof(__u64),

	.size_value = sizeof(__u64),

	.pinning = 2,

	.max_elem = 1024,

};



static unsigned int log2(unsigned int v)

{

	unsigned int r;

	unsigned int shift;



	r = (v > 0xFFFF) << 4; v >>= r;

	shift = (v > 0xFF) << 3; v >>= shift; r |= shift;

	shift = (v > 0xF) << 2; v >>= shift; r |= shift;

	shift = (v > 0x3) << 1; v >>= shift; r |= shift;

	r |= (v >> 1);

	return r;

}



static unsigned int log2l(unsigned long v)

{

	unsigned int hi = v >> 32;

	if (hi)

		return log2(hi) + 32;

	else

		return log2(v);

}



SEC("len_hist")

int do_len_hist(struct __sk_buff *skb)

{

	__u64 *value, key, init_val = 1;



	key = log2l(skb->len);



	value = bpf_map_lookup_elem(&lwt_len_hist_map, &key);

	if (value)

		__sync_fetch_and_add(value, 1);

	else

		bpf_map_update_elem(&lwt_len_hist_map, &key, &init_val, BPF_ANY);



	return BPF_OK;

}



char _license[] SEC("license") = "GPL";

samples/bpf/lwt_len_hist_user.c

0 → 100644
+76 −0
Original line number Diff line number Diff line 
#include <linux/unistd.h>

#include <linux/bpf.h>



#include <stdlib.h>

#include <stdio.h>

#include <unistd.h>

#include <string.h>

#include <errno.h>

#include <arpa/inet.h>



#include "libbpf.h"

#include "bpf_util.h"



#define MAX_INDEX 64

#define MAX_STARS 38



static void stars(char *str, long val, long max, int width)

{

	int i;



	for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++)

		str[i] = '*';

	if (val > max)

		str[i - 1] = '+';

	str[i] = '\0';

}



int main(int argc, char **argv)

{

	unsigned int nr_cpus = bpf_num_possible_cpus();

	const char *map_filename = "/sys/fs/bpf/tc/globals/lwt_len_hist_map";

	uint64_t values[nr_cpus], sum, max_value = 0, data[MAX_INDEX] = {};

	uint64_t key = 0, next_key, max_key = 0;

	char starstr[MAX_STARS];

	int i, map_fd;



	map_fd = bpf_obj_get(map_filename);

	if (map_fd < 0) {

		fprintf(stderr, "bpf_obj_get(%s): %s(%d)\n",

			map_filename, strerror(errno), errno);

		return -1;

	}



	while (bpf_get_next_key(map_fd, &key, &next_key) == 0) {

		if (next_key >= MAX_INDEX) {

			fprintf(stderr, "Key %lu out of bounds\n", next_key);

			continue;

		}



		bpf_lookup_elem(map_fd, &next_key, values);



		sum = 0;

		for (i = 0; i < nr_cpus; i++)

			sum += values[i];



		data[next_key] = sum;

		if (sum && next_key > max_key)

			max_key = next_key;



		if (sum > max_value)

			max_value = sum;



		key = next_key;

	}



	for (i = 1; i <= max_key + 1; i++) {

		stars(starstr, data[i - 1], max_value, MAX_STARS);

		printf("%8ld -> %-8ld : %-8ld |%-*s|\n",

		       (1l << i) >> 1, (1l << i) - 1, data[i - 1],

		       MAX_STARS, starstr);

	}



	close(map_fd);



	return 0;

}