Commit ffb65f27 authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller
Browse files

bpf: add a testsuite for eBPF maps 



. check error conditions and sanity of hash and array map APIs
. check large maps (that kernel gracefully switches to vmalloc from kmalloc)
. check multi-process parallel access and stress test

Signed-off-by: default avatarAlexei Starovoitov <ast@plumgrid.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a1854d6a

samples/bpf/Makefile

+2 −1
Original line number Diff line number Diff line
@@ -2,9 +2,10 @@ 
obj- := dummy.o



# List of programs to build

hostprogs-y := test_verifier

hostprogs-y := test_verifier test_maps



test_verifier-objs := test_verifier.o libbpf.o

test_maps-objs := test_maps.o libbpf.o



# Tell kbuild to always build the programs

always := $(hostprogs-y)

samples/bpf/libbpf.c

+2 −1
Original line number Diff line number Diff line
@@ -27,12 +27,13 @@ int bpf_create_map(enum bpf_map_type map_type, int key_size, int value_size, 
	return syscall(__NR_bpf, BPF_MAP_CREATE, &attr, sizeof(attr));

}



int bpf_update_elem(int fd, void *key, void *value)

int bpf_update_elem(int fd, void *key, void *value, unsigned long long flags)

{

	union bpf_attr attr = {

		.map_fd = fd,

		.key = ptr_to_u64(key),

		.value = ptr_to_u64(value),

		.flags = flags,

	};



	return syscall(__NR_bpf, BPF_MAP_UPDATE_ELEM, &attr, sizeof(attr));

samples/bpf/libbpf.h

+1 −1
Original line number Diff line number Diff line
@@ -6,7 +6,7 @@ struct bpf_insn; 


int bpf_create_map(enum bpf_map_type map_type, int key_size, int value_size,

		   int max_entries);

int bpf_update_elem(int fd, void *key, void *value);

int bpf_update_elem(int fd, void *key, void *value, unsigned long long flags);

int bpf_lookup_elem(int fd, void *key, void *value);

int bpf_delete_elem(int fd, void *key);

int bpf_get_next_key(int fd, void *key, void *next_key);

samples/bpf/test_maps.c

0 → 100644
+291 −0
Original line number Diff line number Diff line 
/*

 * Testsuite for eBPF maps

 *

 * Copyright (c) 2014 PLUMgrid, http://plumgrid.com

 *

 * 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.

 */

#include <stdio.h>

#include <unistd.h>

#include <linux/bpf.h>

#include <errno.h>

#include <string.h>

#include <assert.h>

#include <sys/wait.h>

#include <stdlib.h>

#include "libbpf.h"



/* sanity tests for map API */

static void test_hashmap_sanity(int i, void *data)

{

	long long key, next_key, value;

	int map_fd;



	map_fd = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(key), sizeof(value), 2);

	if (map_fd < 0) {

		printf("failed to create hashmap '%s'\n", strerror(errno));

		exit(1);

	}



	key = 1;

	value = 1234;

	/* insert key=1 element */

	assert(bpf_update_elem(map_fd, &key, &value, BPF_ANY) == 0);



	value = 0;

	/* BPF_NOEXIST means: add new element if it doesn't exist */

	assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == -1 &&

	       /* key=1 already exists */

	       errno == EEXIST);



	assert(bpf_update_elem(map_fd, &key, &value, -1) == -1 && errno == EINVAL);



	/* check that key=1 can be found */

	assert(bpf_lookup_elem(map_fd, &key, &value) == 0 && value == 1234);



	key = 2;

	/* check that key=2 is not found */

	assert(bpf_lookup_elem(map_fd, &key, &value) == -1 && errno == ENOENT);



	/* BPF_EXIST means: update existing element */

	assert(bpf_update_elem(map_fd, &key, &value, BPF_EXIST) == -1 &&

	       /* key=2 is not there */

	       errno == ENOENT);



	/* insert key=2 element */

	assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == 0);



	/* key=1 and key=2 were inserted, check that key=0 cannot be inserted

	 * due to max_entries limit

	 */

	key = 0;

	assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == -1 &&

	       errno == E2BIG);



	/* check that key = 0 doesn't exist */

	assert(bpf_delete_elem(map_fd, &key) == -1 && errno == ENOENT);



	/* iterate over two elements */

	assert(bpf_get_next_key(map_fd, &key, &next_key) == 0 &&

	       next_key == 2);

	assert(bpf_get_next_key(map_fd, &next_key, &next_key) == 0 &&

	       next_key == 1);

	assert(bpf_get_next_key(map_fd, &next_key, &next_key) == -1 &&

	       errno == ENOENT);



	/* delete both elements */

	key = 1;

	assert(bpf_delete_elem(map_fd, &key) == 0);

	key = 2;

	assert(bpf_delete_elem(map_fd, &key) == 0);

	assert(bpf_delete_elem(map_fd, &key) == -1 && errno == ENOENT);



	key = 0;

	/* check that map is empty */

	assert(bpf_get_next_key(map_fd, &key, &next_key) == -1 &&

	       errno == ENOENT);

	close(map_fd);

}



static void test_arraymap_sanity(int i, void *data)

{

	int key, next_key, map_fd;

	long long value;



	map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, sizeof(key), sizeof(value), 2);

	if (map_fd < 0) {

		printf("failed to create arraymap '%s'\n", strerror(errno));

		exit(1);

	}



	key = 1;

	value = 1234;

	/* insert key=1 element */

	assert(bpf_update_elem(map_fd, &key, &value, BPF_ANY) == 0);



	value = 0;

	assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == -1 &&

	       errno == EEXIST);



	/* check that key=1 can be found */

	assert(bpf_lookup_elem(map_fd, &key, &value) == 0 && value == 1234);



	key = 0;

	/* check that key=0 is also found and zero initialized */

	assert(bpf_lookup_elem(map_fd, &key, &value) == 0 && value == 0);





	/* key=0 and key=1 were inserted, check that key=2 cannot be inserted

	 * due to max_entries limit

	 */

	key = 2;

	assert(bpf_update_elem(map_fd, &key, &value, BPF_EXIST) == -1 &&

	       errno == E2BIG);



	/* check that key = 2 doesn't exist */

	assert(bpf_lookup_elem(map_fd, &key, &value) == -1 && errno == ENOENT);



	/* iterate over two elements */

	assert(bpf_get_next_key(map_fd, &key, &next_key) == 0 &&

	       next_key == 0);

	assert(bpf_get_next_key(map_fd, &next_key, &next_key) == 0 &&

	       next_key == 1);

	assert(bpf_get_next_key(map_fd, &next_key, &next_key) == -1 &&

	       errno == ENOENT);



	/* delete shouldn't succeed */

	key = 1;

	assert(bpf_delete_elem(map_fd, &key) == -1 && errno == EINVAL);



	close(map_fd);

}



#define MAP_SIZE (32 * 1024)

static void test_map_large(void)

{

	struct bigkey {

		int a;

		char b[116];

		long long c;

	} key;

	int map_fd, i, value;



	/* allocate 4Mbyte of memory */

	map_fd = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(key), sizeof(value),

				MAP_SIZE);

	if (map_fd < 0) {

		printf("failed to create large map '%s'\n", strerror(errno));

		exit(1);

	}



	for (i = 0; i < MAP_SIZE; i++) {

		key = (struct bigkey) {.c = i};

		value = i;

		assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == 0);

	}

	key.c = -1;

	assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == -1 &&

	       errno == E2BIG);



	/* iterate through all elements */

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

		assert(bpf_get_next_key(map_fd, &key, &key) == 0);

	assert(bpf_get_next_key(map_fd, &key, &key) == -1 && errno == ENOENT);



	key.c = 0;

	assert(bpf_lookup_elem(map_fd, &key, &value) == 0 && value == 0);

	key.a = 1;

	assert(bpf_lookup_elem(map_fd, &key, &value) == -1 && errno == ENOENT);



	close(map_fd);

}



/* fork N children and wait for them to complete */

static void run_parallel(int tasks, void (*fn)(int i, void *data), void *data)

{

	pid_t pid[tasks];

	int i;



	for (i = 0; i < tasks; i++) {

		pid[i] = fork();

		if (pid[i] == 0) {

			fn(i, data);

			exit(0);

		} else if (pid[i] == -1) {

			printf("couldn't spawn #%d process\n", i);

			exit(1);

		}

	}

	for (i = 0; i < tasks; i++) {

		int status;



		assert(waitpid(pid[i], &status, 0) == pid[i]);

		assert(status == 0);

	}

}



static void test_map_stress(void)

{

	run_parallel(100, test_hashmap_sanity, NULL);

	run_parallel(100, test_arraymap_sanity, NULL);

}



#define TASKS 1024

#define DO_UPDATE 1

#define DO_DELETE 0

static void do_work(int fn, void *data)

{

	int map_fd = ((int *)data)[0];

	int do_update = ((int *)data)[1];

	int i;

	int key, value;



	for (i = fn; i < MAP_SIZE; i += TASKS) {

		key = value = i;

		if (do_update)

			assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == 0);

		else

			assert(bpf_delete_elem(map_fd, &key) == 0);

	}

}



static void test_map_parallel(void)

{

	int i, map_fd, key = 0, value = 0;

	int data[2];



	map_fd = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(key), sizeof(value),

				MAP_SIZE);

	if (map_fd < 0) {

		printf("failed to create map for parallel test '%s'\n",

		       strerror(errno));

		exit(1);

	}



	data[0] = map_fd;

	data[1] = DO_UPDATE;

	/* use the same map_fd in children to add elements to this map

	 * child_0 adds key=0, key=1024, key=2048, ...

	 * child_1 adds key=1, key=1025, key=2049, ...

	 * child_1023 adds key=1023, ...

	 */

	run_parallel(TASKS, do_work, data);



	/* check that key=0 is already there */

	assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == -1 &&

	       errno == EEXIST);



	/* check that all elements were inserted */

	key = -1;

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

		assert(bpf_get_next_key(map_fd, &key, &key) == 0);

	assert(bpf_get_next_key(map_fd, &key, &key) == -1 && errno == ENOENT);



	/* another check for all elements */

	for (i = 0; i < MAP_SIZE; i++) {

		key = MAP_SIZE - i - 1;

		assert(bpf_lookup_elem(map_fd, &key, &value) == 0 &&

		       value == key);

	}



	/* now let's delete all elemenets in parallel */

	data[1] = DO_DELETE;

	run_parallel(TASKS, do_work, data);



	/* nothing should be left */

	key = -1;

	assert(bpf_get_next_key(map_fd, &key, &key) == -1 && errno == ENOENT);

}



int main(void)

{

	test_hashmap_sanity(0, NULL);

	test_arraymap_sanity(0, NULL);

	test_map_large();

	test_map_parallel();

	test_map_stress();

	printf("test_maps: OK\n");

	return 0;

}

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