[PATCH net-next 5/7] bpf: add a testsuite for eBPF maps

Alexei Starovoitov
2014-11-04T02:54:47Z

. 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: Alexei Starovoitov <ast@plumgrid.com>
---
Eventually it can be moved tools/testing/selftests/bpf/, but for now keep
it in samples/bpf/, since that's where all subsequent samples are coming to.

samples/bpf/Makefile | 3 +-
samples/bpf/libbpf.c | 3 +-
samples/bpf/libbpf.h | 2 +-
samples/bpf/test_maps.c | 287 +++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 292 insertions(+), 3 deletions(-)
create mode 100644 samples/bpf/test_maps.c

diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile
index 634391797856..0718d9ce4619 100644
--- a/samples/bpf/Makefile
+++ b/samples/bpf/Makefile
@@ -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)
diff --git a/samples/bpf/libbpf.c b/samples/bpf/libbpf.c
index ff6504420738..17bb520eb57f 100644
--- a/samples/bpf/libbpf.c
+++ b/samples/bpf/libbpf.c
@@ -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));
diff --git a/samples/bpf/libbpf.h b/samples/bpf/libbpf.h
index 8a31babeca5d..f8678e5f48bf 100644
--- a/samples/bpf/libbpf.h
+++ b/samples/bpf/libbpf.h
@@ -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);
diff --git a/samples/bpf/test_maps.c b/samples/bpf/test_maps.c
new file mode 100644
index 000000000000..91614031aed0
--- /dev/null
+++ b/samples/bpf/test_maps.c
@@ -0,0 +1,287 @@
+/*
+ * 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_MAP_UPDATE_OR_CREATE) == 0);
+
+ value = 0;
+ assert(bpf_update_elem(map_fd, &key, &value, BPF_MAP_CREATE_ONLY) == -1 &&
+ 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);
+
+ assert(bpf_update_elem(map_fd, &key, &value, BPF_MAP_UPDATE_ONLY) == -1 &&
+ errno == ENOENT);
+
+ /* insert key=2 element */
+ assert(bpf_update_elem(map_fd, &key, &value, BPF_MAP_CREATE_ONLY) == 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_MAP_CREATE_ONLY) == -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_MAP_UPDATE_OR_CREATE) == 0);
+
+ value = 0;
+ assert(bpf_update_elem(map_fd, &key, &value, BPF_MAP_CREATE_ONLY) == -1 &&
+ errno == EINVAL);
+
+ /* 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_MAP_UPDATE_ONLY) == -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_MAP_CREATE_ONLY) == 0);
+ }
+ key.c = -1;
+ assert(bpf_update_elem(map_fd, &key, &value, BPF_MAP_CREATE_ONLY) == -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_MAP_CREATE_ONLY) == 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_MAP_CREATE_ONLY) == -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;
+}
--
1.7.9.5