1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2020 Facebook */ 3 #include "bpf_iter.h" 4 #include <bpf/bpf_helpers.h> 5 #include <bpf/bpf_tracing.h> 6 7 char _license[] SEC("license") = "GPL"; 8 9 struct key_t { 10 int a; 11 int b; 12 int c; 13 }; 14 15 struct { 16 __uint(type, BPF_MAP_TYPE_HASH); 17 __uint(max_entries, 3); 18 __type(key, struct key_t); 19 __type(value, __u64); 20 } hashmap1 SEC(".maps"); 21 22 struct { 23 __uint(type, BPF_MAP_TYPE_HASH); 24 __uint(max_entries, 3); 25 __type(key, __u64); 26 __type(value, __u64); 27 } hashmap2 SEC(".maps"); 28 29 struct { 30 __uint(type, BPF_MAP_TYPE_HASH); 31 __uint(max_entries, 3); 32 __type(key, struct key_t); 33 __type(value, __u32); 34 } hashmap3 SEC(".maps"); 35 36 /* will set before prog run */ 37 bool in_test_mode = 0; 38 39 /* will collect results during prog run */ 40 __u32 key_sum_a = 0, key_sum_b = 0, key_sum_c = 0; 41 __u64 val_sum = 0; 42 43 SEC("iter/bpf_map_elem") 44 int dump_bpf_hash_map(struct bpf_iter__bpf_map_elem *ctx) 45 { 46 struct seq_file *seq = ctx->meta->seq; 47 __u32 seq_num = ctx->meta->seq_num; 48 struct bpf_map *map = ctx->map; 49 struct key_t *key = ctx->key; 50 struct key_t tmp_key; 51 __u64 *val = ctx->value; 52 __u64 tmp_val = 0; 53 int ret; 54 55 if (in_test_mode) { 56 /* test mode is used by selftests to 57 * test functionality of bpf_hash_map iter. 58 * 59 * the above hashmap1 will have correct size 60 * and will be accepted, hashmap2 and hashmap3 61 * should be rejected due to smaller key/value 62 * size. 63 */ 64 if (key == (void *)0 || val == (void *)0) 65 return 0; 66 67 /* update the value and then delete the <key, value> pair. 68 * it should not impact the existing 'val' which is still 69 * accessible under rcu. 70 */ 71 __builtin_memcpy(&tmp_key, key, sizeof(struct key_t)); 72 ret = bpf_map_update_elem(&hashmap1, &tmp_key, &tmp_val, 0); 73 if (ret) 74 return 0; 75 ret = bpf_map_delete_elem(&hashmap1, &tmp_key); 76 if (ret) 77 return 0; 78 79 key_sum_a += key->a; 80 key_sum_b += key->b; 81 key_sum_c += key->c; 82 val_sum += *val; 83 return 0; 84 } 85 86 /* non-test mode, the map is prepared with the 87 * below bpftool command sequence: 88 * bpftool map create /sys/fs/bpf/m1 type hash \ 89 * key 12 value 8 entries 3 name map1 90 * bpftool map update id 77 key 0 0 0 1 0 0 0 0 0 0 0 1 \ 91 * value 0 0 0 1 0 0 0 1 92 * bpftool map update id 77 key 0 0 0 1 0 0 0 0 0 0 0 2 \ 93 * value 0 0 0 1 0 0 0 2 94 * The bpftool iter command line: 95 * bpftool iter pin ./bpf_iter_bpf_hash_map.o /sys/fs/bpf/p1 \ 96 * map id 77 97 * The below output will be: 98 * map dump starts 99 * 77: (1000000 0 2000000) (200000001000000) 100 * 77: (1000000 0 1000000) (100000001000000) 101 * map dump ends 102 */ 103 if (seq_num == 0) 104 BPF_SEQ_PRINTF(seq, "map dump starts\n"); 105 106 if (key == (void *)0 || val == (void *)0) { 107 BPF_SEQ_PRINTF(seq, "map dump ends\n"); 108 return 0; 109 } 110 111 BPF_SEQ_PRINTF(seq, "%d: (%x %d %x) (%llx)\n", map->id, 112 key->a, key->b, key->c, *val); 113 114 return 0; 115 } 116