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-rw-r--r--include/linux/bpf.h1
-rw-r--r--include/linux/bpf_types.h1
-rw-r--r--include/uapi/linux/bpf.h9
-rw-r--r--kernel/bpf/Makefile2
-rw-r--r--kernel/bpf/bloom_filter.c195
-rw-r--r--kernel/bpf/syscall.c24
-rw-r--r--kernel/bpf/verifier.c19
-rw-r--r--tools/include/uapi/linux/bpf.h9
8 files changed, 253 insertions, 7 deletions
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 31421c74ba08..50105e0b8fcc 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -169,6 +169,7 @@ struct bpf_map {
u32 value_size;
u32 max_entries;
u32 map_flags;
+ u64 map_extra; /* any per-map-type extra fields */
int spin_lock_off; /* >=0 valid offset, <0 error */
int timer_off; /* >=0 valid offset, <0 error */
u32 id;
diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h
index 9c81724e4b98..c4424ac2fa02 100644
--- a/include/linux/bpf_types.h
+++ b/include/linux/bpf_types.h
@@ -125,6 +125,7 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_STACK, stack_map_ops)
BPF_MAP_TYPE(BPF_MAP_TYPE_STRUCT_OPS, bpf_struct_ops_map_ops)
#endif
BPF_MAP_TYPE(BPF_MAP_TYPE_RINGBUF, ringbuf_map_ops)
+BPF_MAP_TYPE(BPF_MAP_TYPE_BLOOM_FILTER, bloom_filter_map_ops)
BPF_LINK_TYPE(BPF_LINK_TYPE_RAW_TRACEPOINT, raw_tracepoint)
BPF_LINK_TYPE(BPF_LINK_TYPE_TRACING, tracing)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index c10820037883..8bead4aa3ad0 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -906,6 +906,7 @@ enum bpf_map_type {
BPF_MAP_TYPE_RINGBUF,
BPF_MAP_TYPE_INODE_STORAGE,
BPF_MAP_TYPE_TASK_STORAGE,
+ BPF_MAP_TYPE_BLOOM_FILTER,
};
/* Note that tracing related programs such as
@@ -1274,6 +1275,13 @@ union bpf_attr {
* struct stored as the
* map value
*/
+ /* Any per-map-type extra fields
+ *
+ * BPF_MAP_TYPE_BLOOM_FILTER - the lowest 4 bits indicate the
+ * number of hash functions (if 0, the bloom filter will default
+ * to using 5 hash functions).
+ */
+ __u64 map_extra;
};
struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
@@ -5638,6 +5646,7 @@ struct bpf_map_info {
__u32 btf_id;
__u32 btf_key_type_id;
__u32 btf_value_type_id;
+ __u64 map_extra;
} __attribute__((aligned(8)));
struct bpf_btf_info {
diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
index 7f33098ca63f..cf6ca339f3cd 100644
--- a/kernel/bpf/Makefile
+++ b/kernel/bpf/Makefile
@@ -7,7 +7,7 @@ endif
CFLAGS_core.o += $(call cc-disable-warning, override-init) $(cflags-nogcse-yy)
obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o inode.o helpers.o tnum.o bpf_iter.o map_iter.o task_iter.o prog_iter.o
-obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o
+obj-$(CONFIG_BPF_SYSCALL) += hashtab.o arraymap.o percpu_freelist.o bpf_lru_list.o lpm_trie.o map_in_map.o bloom_filter.o
obj-$(CONFIG_BPF_SYSCALL) += local_storage.o queue_stack_maps.o ringbuf.o
obj-$(CONFIG_BPF_SYSCALL) += bpf_local_storage.o bpf_task_storage.o
obj-${CONFIG_BPF_LSM} += bpf_inode_storage.o
diff --git a/kernel/bpf/bloom_filter.c b/kernel/bpf/bloom_filter.c
new file mode 100644
index 000000000000..7c50232b7571
--- /dev/null
+++ b/kernel/bpf/bloom_filter.c
@@ -0,0 +1,195 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2021 Facebook */
+
+#include <linux/bitmap.h>
+#include <linux/bpf.h>
+#include <linux/btf.h>
+#include <linux/err.h>
+#include <linux/jhash.h>
+#include <linux/random.h>
+
+#define BLOOM_CREATE_FLAG_MASK \
+ (BPF_F_NUMA_NODE | BPF_F_ZERO_SEED | BPF_F_ACCESS_MASK)
+
+struct bpf_bloom_filter {
+ struct bpf_map map;
+ u32 bitset_mask;
+ u32 hash_seed;
+ /* If the size of the values in the bloom filter is u32 aligned,
+ * then it is more performant to use jhash2 as the underlying hash
+ * function, else we use jhash. This tracks the number of u32s
+ * in an u32-aligned value size. If the value size is not u32 aligned,
+ * this will be 0.
+ */
+ u32 aligned_u32_count;
+ u32 nr_hash_funcs;
+ unsigned long bitset[];
+};
+
+static u32 hash(struct bpf_bloom_filter *bloom, void *value,
+ u32 value_size, u32 index)
+{
+ u32 h;
+
+ if (bloom->aligned_u32_count)
+ h = jhash2(value, bloom->aligned_u32_count,
+ bloom->hash_seed + index);
+ else
+ h = jhash(value, value_size, bloom->hash_seed + index);
+
+ return h & bloom->bitset_mask;
+}
+
+static int peek_elem(struct bpf_map *map, void *value)
+{
+ struct bpf_bloom_filter *bloom =
+ container_of(map, struct bpf_bloom_filter, map);
+ u32 i, h;
+
+ for (i = 0; i < bloom->nr_hash_funcs; i++) {
+ h = hash(bloom, value, map->value_size, i);
+ if (!test_bit(h, bloom->bitset))
+ return -ENOENT;
+ }
+
+ return 0;
+}
+
+static int push_elem(struct bpf_map *map, void *value, u64 flags)
+{
+ struct bpf_bloom_filter *bloom =
+ container_of(map, struct bpf_bloom_filter, map);
+ u32 i, h;
+
+ if (flags != BPF_ANY)
+ return -EINVAL;
+
+ for (i = 0; i < bloom->nr_hash_funcs; i++) {
+ h = hash(bloom, value, map->value_size, i);
+ set_bit(h, bloom->bitset);
+ }
+
+ return 0;
+}
+
+static int pop_elem(struct bpf_map *map, void *value)
+{
+ return -EOPNOTSUPP;
+}
+
+static struct bpf_map *map_alloc(union bpf_attr *attr)
+{
+ u32 bitset_bytes, bitset_mask, nr_hash_funcs, nr_bits;
+ int numa_node = bpf_map_attr_numa_node(attr);
+ struct bpf_bloom_filter *bloom;
+
+ if (!bpf_capable())
+ return ERR_PTR(-EPERM);
+
+ if (attr->key_size != 0 || attr->value_size == 0 ||
+ attr->max_entries == 0 ||
+ attr->map_flags & ~BLOOM_CREATE_FLAG_MASK ||
+ !bpf_map_flags_access_ok(attr->map_flags) ||
+ (attr->map_extra & ~0xF))
+ return ERR_PTR(-EINVAL);
+
+ /* The lower 4 bits of map_extra specify the number of hash functions */
+ nr_hash_funcs = attr->map_extra & 0xF;
+ if (nr_hash_funcs == 0)
+ /* Default to using 5 hash functions if unspecified */
+ nr_hash_funcs = 5;
+
+ /* For the bloom filter, the optimal bit array size that minimizes the
+ * false positive probability is n * k / ln(2) where n is the number of
+ * expected entries in the bloom filter and k is the number of hash
+ * functions. We use 7 / 5 to approximate 1 / ln(2).
+ *
+ * We round this up to the nearest power of two to enable more efficient
+ * hashing using bitmasks. The bitmask will be the bit array size - 1.
+ *
+ * If this overflows a u32, the bit array size will have 2^32 (4
+ * GB) bits.
+ */
+ if (check_mul_overflow(attr->max_entries, nr_hash_funcs, &nr_bits) ||
+ check_mul_overflow(nr_bits / 5, (u32)7, &nr_bits) ||
+ nr_bits > (1UL << 31)) {
+ /* The bit array size is 2^32 bits but to avoid overflowing the
+ * u32, we use U32_MAX, which will round up to the equivalent
+ * number of bytes
+ */
+ bitset_bytes = BITS_TO_BYTES(U32_MAX);
+ bitset_mask = U32_MAX;
+ } else {
+ if (nr_bits <= BITS_PER_LONG)
+ nr_bits = BITS_PER_LONG;
+ else
+ nr_bits = roundup_pow_of_two(nr_bits);
+ bitset_bytes = BITS_TO_BYTES(nr_bits);
+ bitset_mask = nr_bits - 1;
+ }
+
+ bitset_bytes = roundup(bitset_bytes, sizeof(unsigned long));
+ bloom = bpf_map_area_alloc(sizeof(*bloom) + bitset_bytes, numa_node);
+
+ if (!bloom)
+ return ERR_PTR(-ENOMEM);
+
+ bpf_map_init_from_attr(&bloom->map, attr);
+
+ bloom->nr_hash_funcs = nr_hash_funcs;
+ bloom->bitset_mask = bitset_mask;
+
+ /* Check whether the value size is u32-aligned */
+ if ((attr->value_size & (sizeof(u32) - 1)) == 0)
+ bloom->aligned_u32_count =
+ attr->value_size / sizeof(u32);
+
+ if (!(attr->map_flags & BPF_F_ZERO_SEED))
+ bloom->hash_seed = get_random_int();
+
+ return &bloom->map;
+}
+
+static void map_free(struct bpf_map *map)
+{
+ struct bpf_bloom_filter *bloom =
+ container_of(map, struct bpf_bloom_filter, map);
+
+ bpf_map_area_free(bloom);
+}
+
+static void *lookup_elem(struct bpf_map *map, void *key)
+{
+ /* The eBPF program should use map_peek_elem instead */
+ return ERR_PTR(-EINVAL);
+}
+
+static int update_elem(struct bpf_map *map, void *key,
+ void *value, u64 flags)
+{
+ /* The eBPF program should use map_push_elem instead */
+ return -EINVAL;
+}
+
+static int check_btf(const struct bpf_map *map, const struct btf *btf,
+ const struct btf_type *key_type,
+ const struct btf_type *value_type)
+{
+ /* Bloom filter maps are keyless */
+ return btf_type_is_void(key_type) ? 0 : -EINVAL;
+}
+
+static int bpf_bloom_btf_id;
+const struct bpf_map_ops bloom_filter_map_ops = {
+ .map_meta_equal = bpf_map_meta_equal,
+ .map_alloc = map_alloc,
+ .map_free = map_free,
+ .map_push_elem = push_elem,
+ .map_peek_elem = peek_elem,
+ .map_pop_elem = pop_elem,
+ .map_lookup_elem = lookup_elem,
+ .map_update_elem = update_elem,
+ .map_check_btf = check_btf,
+ .map_btf_name = "bpf_bloom_filter",
+ .map_btf_id = &bpf_bloom_btf_id,
+};
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 3e1c024ce3ed..f7c2c6354add 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -199,7 +199,8 @@ static int bpf_map_update_value(struct bpf_map *map, struct fd f, void *key,
err = bpf_fd_reuseport_array_update_elem(map, key, value,
flags);
} else if (map->map_type == BPF_MAP_TYPE_QUEUE ||
- map->map_type == BPF_MAP_TYPE_STACK) {
+ map->map_type == BPF_MAP_TYPE_STACK ||
+ map->map_type == BPF_MAP_TYPE_BLOOM_FILTER) {
err = map->ops->map_push_elem(map, value, flags);
} else {
rcu_read_lock();
@@ -238,7 +239,8 @@ static int bpf_map_copy_value(struct bpf_map *map, void *key, void *value,
} else if (map->map_type == BPF_MAP_TYPE_REUSEPORT_SOCKARRAY) {
err = bpf_fd_reuseport_array_lookup_elem(map, key, value);
} else if (map->map_type == BPF_MAP_TYPE_QUEUE ||
- map->map_type == BPF_MAP_TYPE_STACK) {
+ map->map_type == BPF_MAP_TYPE_STACK ||
+ map->map_type == BPF_MAP_TYPE_BLOOM_FILTER) {
err = map->ops->map_peek_elem(map, value);
} else if (map->map_type == BPF_MAP_TYPE_STRUCT_OPS) {
/* struct_ops map requires directly updating "value" */
@@ -348,6 +350,7 @@ void bpf_map_init_from_attr(struct bpf_map *map, union bpf_attr *attr)
map->max_entries = attr->max_entries;
map->map_flags = bpf_map_flags_retain_permanent(attr->map_flags);
map->numa_node = bpf_map_attr_numa_node(attr);
+ map->map_extra = attr->map_extra;
}
static int bpf_map_alloc_id(struct bpf_map *map)
@@ -553,6 +556,7 @@ static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
"value_size:\t%u\n"
"max_entries:\t%u\n"
"map_flags:\t%#x\n"
+ "map_extra:\t%#llx\n"
"memlock:\t%lu\n"
"map_id:\t%u\n"
"frozen:\t%u\n",
@@ -561,6 +565,7 @@ static void bpf_map_show_fdinfo(struct seq_file *m, struct file *filp)
map->value_size,
map->max_entries,
map->map_flags,
+ (unsigned long long)map->map_extra,
bpf_map_memory_footprint(map),
map->id,
READ_ONCE(map->frozen));
@@ -810,7 +815,7 @@ static int map_check_btf(struct bpf_map *map, const struct btf *btf,
return ret;
}
-#define BPF_MAP_CREATE_LAST_FIELD btf_vmlinux_value_type_id
+#define BPF_MAP_CREATE_LAST_FIELD map_extra
/* called via syscall */
static int map_create(union bpf_attr *attr)
{
@@ -831,6 +836,10 @@ static int map_create(union bpf_attr *attr)
return -EINVAL;
}
+ if (attr->map_type != BPF_MAP_TYPE_BLOOM_FILTER &&
+ attr->map_extra != 0)
+ return -EINVAL;
+
f_flags = bpf_get_file_flag(attr->map_flags);
if (f_flags < 0)
return f_flags;
@@ -1080,6 +1089,14 @@ static int map_lookup_elem(union bpf_attr *attr)
if (!value)
goto free_key;
+ if (map->map_type == BPF_MAP_TYPE_BLOOM_FILTER) {
+ if (copy_from_user(value, uvalue, value_size))
+ err = -EFAULT;
+ else
+ err = bpf_map_copy_value(map, key, value, attr->flags);
+ goto free_value;
+ }
+
err = bpf_map_copy_value(map, key, value, attr->flags);
if (err)
goto free_value;
@@ -3881,6 +3898,7 @@ static int bpf_map_get_info_by_fd(struct file *file,
info.value_size = map->value_size;
info.max_entries = map->max_entries;
info.map_flags = map->map_flags;
+ info.map_extra = map->map_extra;
memcpy(info.name, map->name, sizeof(map->name));
if (map->btf) {
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index c6616e325803..3c8aa7df1773 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -5002,7 +5002,10 @@ static int resolve_map_arg_type(struct bpf_verifier_env *env,
return -EINVAL;
}
break;
-
+ case BPF_MAP_TYPE_BLOOM_FILTER:
+ if (meta->func_id == BPF_FUNC_map_peek_elem)
+ *arg_type = ARG_PTR_TO_MAP_VALUE;
+ break;
default:
break;
}
@@ -5577,6 +5580,11 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
func_id != BPF_FUNC_task_storage_delete)
goto error;
break;
+ case BPF_MAP_TYPE_BLOOM_FILTER:
+ if (func_id != BPF_FUNC_map_peek_elem &&
+ func_id != BPF_FUNC_map_push_elem)
+ goto error;
+ break;
default:
break;
}
@@ -5644,13 +5652,18 @@ static int check_map_func_compatibility(struct bpf_verifier_env *env,
map->map_type != BPF_MAP_TYPE_SOCKHASH)
goto error;
break;
- case BPF_FUNC_map_peek_elem:
case BPF_FUNC_map_pop_elem:
- case BPF_FUNC_map_push_elem:
if (map->map_type != BPF_MAP_TYPE_QUEUE &&
map->map_type != BPF_MAP_TYPE_STACK)
goto error;
break;
+ case BPF_FUNC_map_peek_elem:
+ case BPF_FUNC_map_push_elem:
+ if (map->map_type != BPF_MAP_TYPE_QUEUE &&
+ map->map_type != BPF_MAP_TYPE_STACK &&
+ map->map_type != BPF_MAP_TYPE_BLOOM_FILTER)
+ goto error;
+ break;
case BPF_FUNC_sk_storage_get:
case BPF_FUNC_sk_storage_delete:
if (map->map_type != BPF_MAP_TYPE_SK_STORAGE)
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index c10820037883..8bead4aa3ad0 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -906,6 +906,7 @@ enum bpf_map_type {
BPF_MAP_TYPE_RINGBUF,
BPF_MAP_TYPE_INODE_STORAGE,
BPF_MAP_TYPE_TASK_STORAGE,
+ BPF_MAP_TYPE_BLOOM_FILTER,
};
/* Note that tracing related programs such as
@@ -1274,6 +1275,13 @@ union bpf_attr {
* struct stored as the
* map value
*/
+ /* Any per-map-type extra fields
+ *
+ * BPF_MAP_TYPE_BLOOM_FILTER - the lowest 4 bits indicate the
+ * number of hash functions (if 0, the bloom filter will default
+ * to using 5 hash functions).
+ */
+ __u64 map_extra;
};
struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
@@ -5638,6 +5646,7 @@ struct bpf_map_info {
__u32 btf_id;
__u32 btf_key_type_id;
__u32 btf_value_type_id;
+ __u64 map_extra;
} __attribute__((aligned(8)));
struct bpf_btf_info {
generated by cgit (git 2.34.1) at 2024-05-28 21:37:17 +0000