samples/bpf/test_maps.c

   1 /*
   2  * Testsuite for eBPF maps
   3  *
   4  * Copyright (c) 2014 PLUMgrid, http://plumgrid.com
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of version 2 of the GNU General Public
   8  * License as published by the Free Software Foundation.
   9  */
  10 #include <stdio.h>
  11 #include <unistd.h>
  12 #include <linux/bpf.h>
  13 #include <errno.h>
  14 #include <string.h>
  15 #include <assert.h>
  16 #include <sys/wait.h>
  17 #include <stdlib.h>
  18 #include "libbpf.h"
  19
  20 /* sanity tests for map API */
  21 static void test_hashmap_sanity(int i, void *data)
  22 {
  23         long long key, next_key, value;
  24         int map_fd;
  25
  26         map_fd = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(key), sizeof(value), 2);
  27         if (map_fd < 0) {
  28                 printf("failed to create hashmap '%s'\n", strerror(errno));
  29                 exit(1);
  30         }
  31
  32         key = 1;
  33         value = 1234;
  34         /* insert key=1 element */
  35         assert(bpf_update_elem(map_fd, &key, &value, BPF_ANY) == 0);
  36
  37         value = 0;
  38         /* BPF_NOEXIST means: add new element if it doesn't exist */
  39         assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == -1 &&
  40                /* key=1 already exists */
  41                errno == EEXIST);
  42
  43         assert(bpf_update_elem(map_fd, &key, &value, -1) == -1 && errno == EINVAL);
  44
  45         /* check that key=1 can be found */
  46         assert(bpf_lookup_elem(map_fd, &key, &value) == 0 && value == 1234);
  47
  48         key = 2;
  49         /* check that key=2 is not found */
  50         assert(bpf_lookup_elem(map_fd, &key, &value) == -1 && errno == ENOENT);
  51
  52         /* BPF_EXIST means: update existing element */
  53         assert(bpf_update_elem(map_fd, &key, &value, BPF_EXIST) == -1 &&
  54                /* key=2 is not there */
  55                errno == ENOENT);
  56
  57         /* insert key=2 element */
  58         assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == 0);
  59
  60         /* key=1 and key=2 were inserted, check that key=0 cannot be inserted
  61          * due to max_entries limit
  62          */
  63         key = 0;
  64         assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == -1 &&
  65                errno == E2BIG);
  66
  67         /* check that key = 0 doesn't exist */
  68         assert(bpf_delete_elem(map_fd, &key) == -1 && errno == ENOENT);
  69
  70         /* iterate over two elements */
  71         assert(bpf_get_next_key(map_fd, &key, &next_key) == 0 &&
  72                next_key == 2);
  73         assert(bpf_get_next_key(map_fd, &next_key, &next_key) == 0 &&
  74                next_key == 1);
  75         assert(bpf_get_next_key(map_fd, &next_key, &next_key) == -1 &&
  76                errno == ENOENT);
  77
  78         /* delete both elements */
  79         key = 1;
  80         assert(bpf_delete_elem(map_fd, &key) == 0);
  81         key = 2;
  82         assert(bpf_delete_elem(map_fd, &key) == 0);
  83         assert(bpf_delete_elem(map_fd, &key) == -1 && errno == ENOENT);
  84
  85         key = 0;
  86         /* check that map is empty */
  87         assert(bpf_get_next_key(map_fd, &key, &next_key) == -1 &&
  88                errno == ENOENT);
  89         close(map_fd);
  90 }
  91
  92 static void test_arraymap_sanity(int i, void *data)
  93 {
  94         int key, next_key, map_fd;
  95         long long value;
  96
  97         map_fd = bpf_create_map(BPF_MAP_TYPE_ARRAY, sizeof(key), sizeof(value), 2);
  98         if (map_fd < 0) {
  99                 printf("failed to create arraymap '%s'\n", strerror(errno));
 100                 exit(1);
 101         }
 102
 103         key = 1;
 104         value = 1234;
 105         /* insert key=1 element */
 106         assert(bpf_update_elem(map_fd, &key, &value, BPF_ANY) == 0);
 107
 108         value = 0;
 109         assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == -1 &&
 110                errno == EEXIST);
 111
 112         /* check that key=1 can be found */
 113         assert(bpf_lookup_elem(map_fd, &key, &value) == 0 && value == 1234);
 114
 115         key = 0;
 116         /* check that key=0 is also found and zero initialized */
 117         assert(bpf_lookup_elem(map_fd, &key, &value) == 0 && value == 0);
 118
 119
 120         /* key=0 and key=1 were inserted, check that key=2 cannot be inserted
 121          * due to max_entries limit
 122          */
 123         key = 2;
 124         assert(bpf_update_elem(map_fd, &key, &value, BPF_EXIST) == -1 &&
 125                errno == E2BIG);
 126
 127         /* check that key = 2 doesn't exist */
 128         assert(bpf_lookup_elem(map_fd, &key, &value) == -1 && errno == ENOENT);
 129
 130         /* iterate over two elements */
 131         assert(bpf_get_next_key(map_fd, &key, &next_key) == 0 &&
 132                next_key == 0);
 133         assert(bpf_get_next_key(map_fd, &next_key, &next_key) == 0 &&
 134                next_key == 1);
 135         assert(bpf_get_next_key(map_fd, &next_key, &next_key) == -1 &&
 136                errno == ENOENT);
 137
 138         /* delete shouldn't succeed */
 139         key = 1;
 140         assert(bpf_delete_elem(map_fd, &key) == -1 && errno == EINVAL);
 141
 142         close(map_fd);
 143 }
 144
 145 #define MAP_SIZE (32 * 1024)
 146 static void test_map_large(void)
 147 {
 148         struct bigkey {
 149                 int a;
 150                 char b[116];
 151                 long long c;
 152         } key;
 153         int map_fd, i, value;
 154
 155         /* allocate 4Mbyte of memory */
 156         map_fd = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(key), sizeof(value),
 157                                 MAP_SIZE);
 158         if (map_fd < 0) {
 159                 printf("failed to create large map '%s'\n", strerror(errno));
 160                 exit(1);
 161         }
 162
 163         for (i = 0; i < MAP_SIZE; i++) {
 164                 key = (struct bigkey) {.c = i};
 165                 value = i;
 166                 assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == 0);
 167         }
 168         key.c = -1;
 169         assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == -1 &&
 170                errno == E2BIG);
 171
 172         /* iterate through all elements */
 173         for (i = 0; i < MAP_SIZE; i++)
 174                 assert(bpf_get_next_key(map_fd, &key, &key) == 0);
 175         assert(bpf_get_next_key(map_fd, &key, &key) == -1 && errno == ENOENT);
 176
 177         key.c = 0;
 178         assert(bpf_lookup_elem(map_fd, &key, &value) == 0 && value == 0);
 179         key.a = 1;
 180         assert(bpf_lookup_elem(map_fd, &key, &value) == -1 && errno == ENOENT);
 181
 182         close(map_fd);
 183 }
 184
 185 /* fork N children and wait for them to complete */
 186 static void run_parallel(int tasks, void (*fn)(int i, void *data), void *data)
 187 {
 188         pid_t pid[tasks];
 189         int i;
 190
 191         for (i = 0; i < tasks; i++) {
 192                 pid[i] = fork();
 193                 if (pid[i] == 0) {
 194                         fn(i, data);
 195                         exit(0);
 196                 } else if (pid[i] == -1) {
 197                         printf("couldn't spawn #%d process\n", i);
 198                         exit(1);
 199                 }
 200         }
 201         for (i = 0; i < tasks; i++) {
 202                 int status;
 203
 204                 assert(waitpid(pid[i], &status, 0) == pid[i]);
 205                 assert(status == 0);
 206         }
 207 }
 208
 209 static void test_map_stress(void)
 210 {
 211         run_parallel(100, test_hashmap_sanity, NULL);
 212         run_parallel(100, test_arraymap_sanity, NULL);
 213 }
 214
 215 #define TASKS 1024
 216 #define DO_UPDATE 1
 217 #define DO_DELETE 0
 218 static void do_work(int fn, void *data)
 219 {
 220         int map_fd = ((int *)data)[0];
 221         int do_update = ((int *)data)[1];
 222         int i;
 223         int key, value;
 224
 225         for (i = fn; i < MAP_SIZE; i += TASKS) {
 226                 key = value = i;
 227                 if (do_update)
 228                         assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == 0);
 229                 else
 230                         assert(bpf_delete_elem(map_fd, &key) == 0);
 231         }
 232 }
 233
 234 static void test_map_parallel(void)
 235 {
 236         int i, map_fd, key = 0, value = 0;
 237         int data[2];
 238
 239         map_fd = bpf_create_map(BPF_MAP_TYPE_HASH, sizeof(key), sizeof(value),
 240                                 MAP_SIZE);
 241         if (map_fd < 0) {
 242                 printf("failed to create map for parallel test '%s'\n",
 243                        strerror(errno));
 244                 exit(1);
 245         }
 246
 247         data[0] = map_fd;
 248         data[1] = DO_UPDATE;
 249         /* use the same map_fd in children to add elements to this map
 250          * child_0 adds key=0, key=1024, key=2048, ...
 251          * child_1 adds key=1, key=1025, key=2049, ...
 252          * child_1023 adds key=1023, ...
 253          */
 254         run_parallel(TASKS, do_work, data);
 255
 256         /* check that key=0 is already there */
 257         assert(bpf_update_elem(map_fd, &key, &value, BPF_NOEXIST) == -1 &&
 258                errno == EEXIST);
 259
 260         /* check that all elements were inserted */
 261         key = -1;
 262         for (i = 0; i < MAP_SIZE; i++)
 263                 assert(bpf_get_next_key(map_fd, &key, &key) == 0);
 264         assert(bpf_get_next_key(map_fd, &key, &key) == -1 && errno == ENOENT);
 265
 266         /* another check for all elements */
 267         for (i = 0; i < MAP_SIZE; i++) {
 268                 key = MAP_SIZE - i - 1;
 269                 assert(bpf_lookup_elem(map_fd, &key, &value) == 0 &&
 270                        value == key);
 271         }
 272
 273         /* now let's delete all elemenets in parallel */
 274         data[1] = DO_DELETE;
 275         run_parallel(TASKS, do_work, data);
 276
 277         /* nothing should be left */
 278         key = -1;
 279         assert(bpf_get_next_key(map_fd, &key, &key) == -1 && errno == ENOENT);
 280 }
 281
 282 int main(void)
 283 {
 284         test_hashmap_sanity(0, NULL);
 285         test_arraymap_sanity(0, NULL);
 286         test_map_large();
 287         test_map_parallel();
 288         test_map_stress();
 289         printf("test_maps: OK\n");
 290         return 0;
 291 }