646 строки
16 KiB
C
646 строки
16 KiB
C
/* Copyright (c) 2011-2014 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.
|
|
*
|
|
* This program is distributed in the hope that it will be useful, but
|
|
* WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
* General Public License for more details.
|
|
*/
|
|
#include <linux/bpf.h>
|
|
#include <linux/jhash.h>
|
|
#include <linux/filter.h>
|
|
#include <linux/vmalloc.h>
|
|
|
|
struct bucket {
|
|
struct hlist_head head;
|
|
raw_spinlock_t lock;
|
|
};
|
|
|
|
struct bpf_htab {
|
|
struct bpf_map map;
|
|
struct bucket *buckets;
|
|
atomic_t count; /* number of elements in this hashtable */
|
|
u32 n_buckets; /* number of hash buckets */
|
|
u32 elem_size; /* size of each element in bytes */
|
|
};
|
|
|
|
/* each htab element is struct htab_elem + key + value */
|
|
struct htab_elem {
|
|
struct hlist_node hash_node;
|
|
struct rcu_head rcu;
|
|
union {
|
|
u32 hash;
|
|
u32 key_size;
|
|
};
|
|
char key[0] __aligned(8);
|
|
};
|
|
|
|
/* Called from syscall */
|
|
static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
|
|
{
|
|
bool percpu = attr->map_type == BPF_MAP_TYPE_PERCPU_HASH;
|
|
struct bpf_htab *htab;
|
|
int err, i;
|
|
u64 cost;
|
|
|
|
htab = kzalloc(sizeof(*htab), GFP_USER);
|
|
if (!htab)
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
/* mandatory map attributes */
|
|
htab->map.map_type = attr->map_type;
|
|
htab->map.key_size = attr->key_size;
|
|
htab->map.value_size = attr->value_size;
|
|
htab->map.max_entries = attr->max_entries;
|
|
|
|
/* check sanity of attributes.
|
|
* value_size == 0 may be allowed in the future to use map as a set
|
|
*/
|
|
err = -EINVAL;
|
|
if (htab->map.max_entries == 0 || htab->map.key_size == 0 ||
|
|
htab->map.value_size == 0)
|
|
goto free_htab;
|
|
|
|
/* hash table size must be power of 2 */
|
|
htab->n_buckets = roundup_pow_of_two(htab->map.max_entries);
|
|
|
|
err = -E2BIG;
|
|
if (htab->map.key_size > MAX_BPF_STACK)
|
|
/* eBPF programs initialize keys on stack, so they cannot be
|
|
* larger than max stack size
|
|
*/
|
|
goto free_htab;
|
|
|
|
if (htab->map.value_size >= (1 << (KMALLOC_SHIFT_MAX - 1)) -
|
|
MAX_BPF_STACK - sizeof(struct htab_elem))
|
|
/* if value_size is bigger, the user space won't be able to
|
|
* access the elements via bpf syscall. This check also makes
|
|
* sure that the elem_size doesn't overflow and it's
|
|
* kmalloc-able later in htab_map_update_elem()
|
|
*/
|
|
goto free_htab;
|
|
|
|
if (percpu && round_up(htab->map.value_size, 8) > PCPU_MIN_UNIT_SIZE)
|
|
/* make sure the size for pcpu_alloc() is reasonable */
|
|
goto free_htab;
|
|
|
|
htab->elem_size = sizeof(struct htab_elem) +
|
|
round_up(htab->map.key_size, 8);
|
|
if (percpu)
|
|
htab->elem_size += sizeof(void *);
|
|
else
|
|
htab->elem_size += htab->map.value_size;
|
|
|
|
/* prevent zero size kmalloc and check for u32 overflow */
|
|
if (htab->n_buckets == 0 ||
|
|
htab->n_buckets > U32_MAX / sizeof(struct bucket))
|
|
goto free_htab;
|
|
|
|
cost = (u64) htab->n_buckets * sizeof(struct bucket) +
|
|
(u64) htab->elem_size * htab->map.max_entries;
|
|
|
|
if (percpu)
|
|
cost += (u64) round_up(htab->map.value_size, 8) *
|
|
num_possible_cpus() * htab->map.max_entries;
|
|
|
|
if (cost >= U32_MAX - PAGE_SIZE)
|
|
/* make sure page count doesn't overflow */
|
|
goto free_htab;
|
|
|
|
htab->map.pages = round_up(cost, PAGE_SIZE) >> PAGE_SHIFT;
|
|
|
|
err = -ENOMEM;
|
|
htab->buckets = kmalloc_array(htab->n_buckets, sizeof(struct bucket),
|
|
GFP_USER | __GFP_NOWARN);
|
|
|
|
if (!htab->buckets) {
|
|
htab->buckets = vmalloc(htab->n_buckets * sizeof(struct bucket));
|
|
if (!htab->buckets)
|
|
goto free_htab;
|
|
}
|
|
|
|
for (i = 0; i < htab->n_buckets; i++) {
|
|
INIT_HLIST_HEAD(&htab->buckets[i].head);
|
|
raw_spin_lock_init(&htab->buckets[i].lock);
|
|
}
|
|
|
|
atomic_set(&htab->count, 0);
|
|
|
|
return &htab->map;
|
|
|
|
free_htab:
|
|
kfree(htab);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
static inline u32 htab_map_hash(const void *key, u32 key_len)
|
|
{
|
|
return jhash(key, key_len, 0);
|
|
}
|
|
|
|
static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash)
|
|
{
|
|
return &htab->buckets[hash & (htab->n_buckets - 1)];
|
|
}
|
|
|
|
static inline struct hlist_head *select_bucket(struct bpf_htab *htab, u32 hash)
|
|
{
|
|
return &__select_bucket(htab, hash)->head;
|
|
}
|
|
|
|
static struct htab_elem *lookup_elem_raw(struct hlist_head *head, u32 hash,
|
|
void *key, u32 key_size)
|
|
{
|
|
struct htab_elem *l;
|
|
|
|
hlist_for_each_entry_rcu(l, head, hash_node)
|
|
if (l->hash == hash && !memcmp(&l->key, key, key_size))
|
|
return l;
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/* Called from syscall or from eBPF program */
|
|
static void *__htab_map_lookup_elem(struct bpf_map *map, void *key)
|
|
{
|
|
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
|
|
struct hlist_head *head;
|
|
struct htab_elem *l;
|
|
u32 hash, key_size;
|
|
|
|
/* Must be called with rcu_read_lock. */
|
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
|
|
|
key_size = map->key_size;
|
|
|
|
hash = htab_map_hash(key, key_size);
|
|
|
|
head = select_bucket(htab, hash);
|
|
|
|
l = lookup_elem_raw(head, hash, key, key_size);
|
|
|
|
return l;
|
|
}
|
|
|
|
static void *htab_map_lookup_elem(struct bpf_map *map, void *key)
|
|
{
|
|
struct htab_elem *l = __htab_map_lookup_elem(map, key);
|
|
|
|
if (l)
|
|
return l->key + round_up(map->key_size, 8);
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/* Called from syscall */
|
|
static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key)
|
|
{
|
|
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
|
|
struct hlist_head *head;
|
|
struct htab_elem *l, *next_l;
|
|
u32 hash, key_size;
|
|
int i;
|
|
|
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
|
|
|
key_size = map->key_size;
|
|
|
|
hash = htab_map_hash(key, key_size);
|
|
|
|
head = select_bucket(htab, hash);
|
|
|
|
/* lookup the key */
|
|
l = lookup_elem_raw(head, hash, key, key_size);
|
|
|
|
if (!l) {
|
|
i = 0;
|
|
goto find_first_elem;
|
|
}
|
|
|
|
/* key was found, get next key in the same bucket */
|
|
next_l = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(&l->hash_node)),
|
|
struct htab_elem, hash_node);
|
|
|
|
if (next_l) {
|
|
/* if next elem in this hash list is non-zero, just return it */
|
|
memcpy(next_key, next_l->key, key_size);
|
|
return 0;
|
|
}
|
|
|
|
/* no more elements in this hash list, go to the next bucket */
|
|
i = hash & (htab->n_buckets - 1);
|
|
i++;
|
|
|
|
find_first_elem:
|
|
/* iterate over buckets */
|
|
for (; i < htab->n_buckets; i++) {
|
|
head = select_bucket(htab, i);
|
|
|
|
/* pick first element in the bucket */
|
|
next_l = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),
|
|
struct htab_elem, hash_node);
|
|
if (next_l) {
|
|
/* if it's not empty, just return it */
|
|
memcpy(next_key, next_l->key, key_size);
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/* itereated over all buckets and all elements */
|
|
return -ENOENT;
|
|
}
|
|
|
|
|
|
static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
|
|
void __percpu *pptr)
|
|
{
|
|
*(void __percpu **)(l->key + key_size) = pptr;
|
|
}
|
|
|
|
static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
|
|
{
|
|
return *(void __percpu **)(l->key + key_size);
|
|
}
|
|
|
|
static void htab_percpu_elem_free(struct htab_elem *l)
|
|
{
|
|
free_percpu(htab_elem_get_ptr(l, l->key_size));
|
|
kfree(l);
|
|
}
|
|
|
|
static void htab_percpu_elem_free_rcu(struct rcu_head *head)
|
|
{
|
|
struct htab_elem *l = container_of(head, struct htab_elem, rcu);
|
|
|
|
htab_percpu_elem_free(l);
|
|
}
|
|
|
|
static void free_htab_elem(struct htab_elem *l, bool percpu, u32 key_size)
|
|
{
|
|
if (percpu) {
|
|
l->key_size = key_size;
|
|
call_rcu(&l->rcu, htab_percpu_elem_free_rcu);
|
|
} else {
|
|
kfree_rcu(l, rcu);
|
|
}
|
|
}
|
|
|
|
static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key,
|
|
void *value, u32 key_size, u32 hash,
|
|
bool percpu, bool onallcpus)
|
|
{
|
|
u32 size = htab->map.value_size;
|
|
struct htab_elem *l_new;
|
|
void __percpu *pptr;
|
|
|
|
l_new = kmalloc(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN);
|
|
if (!l_new)
|
|
return NULL;
|
|
|
|
memcpy(l_new->key, key, key_size);
|
|
if (percpu) {
|
|
/* round up value_size to 8 bytes */
|
|
size = round_up(size, 8);
|
|
|
|
/* alloc_percpu zero-fills */
|
|
pptr = __alloc_percpu_gfp(size, 8, GFP_ATOMIC | __GFP_NOWARN);
|
|
if (!pptr) {
|
|
kfree(l_new);
|
|
return NULL;
|
|
}
|
|
|
|
if (!onallcpus) {
|
|
/* copy true value_size bytes */
|
|
memcpy(this_cpu_ptr(pptr), value, htab->map.value_size);
|
|
} else {
|
|
int off = 0, cpu;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
bpf_long_memcpy(per_cpu_ptr(pptr, cpu),
|
|
value + off, size);
|
|
off += size;
|
|
}
|
|
}
|
|
htab_elem_set_ptr(l_new, key_size, pptr);
|
|
} else {
|
|
memcpy(l_new->key + round_up(key_size, 8), value, size);
|
|
}
|
|
|
|
l_new->hash = hash;
|
|
return l_new;
|
|
}
|
|
|
|
static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old,
|
|
u64 map_flags)
|
|
{
|
|
if (!l_old && unlikely(atomic_read(&htab->count) >= htab->map.max_entries))
|
|
/* if elem with this 'key' doesn't exist and we've reached
|
|
* max_entries limit, fail insertion of new elem
|
|
*/
|
|
return -E2BIG;
|
|
|
|
if (l_old && map_flags == BPF_NOEXIST)
|
|
/* elem already exists */
|
|
return -EEXIST;
|
|
|
|
if (!l_old && map_flags == BPF_EXIST)
|
|
/* elem doesn't exist, cannot update it */
|
|
return -ENOENT;
|
|
|
|
return 0;
|
|
}
|
|
|
|
/* Called from syscall or from eBPF program */
|
|
static int htab_map_update_elem(struct bpf_map *map, void *key, void *value,
|
|
u64 map_flags)
|
|
{
|
|
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
|
|
struct htab_elem *l_new = NULL, *l_old;
|
|
struct hlist_head *head;
|
|
unsigned long flags;
|
|
struct bucket *b;
|
|
u32 key_size, hash;
|
|
int ret;
|
|
|
|
if (unlikely(map_flags > BPF_EXIST))
|
|
/* unknown flags */
|
|
return -EINVAL;
|
|
|
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
|
|
|
key_size = map->key_size;
|
|
|
|
hash = htab_map_hash(key, key_size);
|
|
|
|
/* allocate new element outside of the lock, since
|
|
* we're most likley going to insert it
|
|
*/
|
|
l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false);
|
|
if (!l_new)
|
|
return -ENOMEM;
|
|
|
|
b = __select_bucket(htab, hash);
|
|
head = &b->head;
|
|
|
|
/* bpf_map_update_elem() can be called in_irq() */
|
|
raw_spin_lock_irqsave(&b->lock, flags);
|
|
|
|
l_old = lookup_elem_raw(head, hash, key, key_size);
|
|
|
|
ret = check_flags(htab, l_old, map_flags);
|
|
if (ret)
|
|
goto err;
|
|
|
|
/* add new element to the head of the list, so that
|
|
* concurrent search will find it before old elem
|
|
*/
|
|
hlist_add_head_rcu(&l_new->hash_node, head);
|
|
if (l_old) {
|
|
hlist_del_rcu(&l_old->hash_node);
|
|
kfree_rcu(l_old, rcu);
|
|
} else {
|
|
atomic_inc(&htab->count);
|
|
}
|
|
raw_spin_unlock_irqrestore(&b->lock, flags);
|
|
return 0;
|
|
err:
|
|
raw_spin_unlock_irqrestore(&b->lock, flags);
|
|
kfree(l_new);
|
|
return ret;
|
|
}
|
|
|
|
static int __htab_percpu_map_update_elem(struct bpf_map *map, void *key,
|
|
void *value, u64 map_flags,
|
|
bool onallcpus)
|
|
{
|
|
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
|
|
struct htab_elem *l_new = NULL, *l_old;
|
|
struct hlist_head *head;
|
|
unsigned long flags;
|
|
struct bucket *b;
|
|
u32 key_size, hash;
|
|
int ret;
|
|
|
|
if (unlikely(map_flags > BPF_EXIST))
|
|
/* unknown flags */
|
|
return -EINVAL;
|
|
|
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
|
|
|
key_size = map->key_size;
|
|
|
|
hash = htab_map_hash(key, key_size);
|
|
|
|
b = __select_bucket(htab, hash);
|
|
head = &b->head;
|
|
|
|
/* bpf_map_update_elem() can be called in_irq() */
|
|
raw_spin_lock_irqsave(&b->lock, flags);
|
|
|
|
l_old = lookup_elem_raw(head, hash, key, key_size);
|
|
|
|
ret = check_flags(htab, l_old, map_flags);
|
|
if (ret)
|
|
goto err;
|
|
|
|
if (l_old) {
|
|
void __percpu *pptr = htab_elem_get_ptr(l_old, key_size);
|
|
u32 size = htab->map.value_size;
|
|
|
|
/* per-cpu hash map can update value in-place */
|
|
if (!onallcpus) {
|
|
memcpy(this_cpu_ptr(pptr), value, size);
|
|
} else {
|
|
int off = 0, cpu;
|
|
|
|
size = round_up(size, 8);
|
|
for_each_possible_cpu(cpu) {
|
|
bpf_long_memcpy(per_cpu_ptr(pptr, cpu),
|
|
value + off, size);
|
|
off += size;
|
|
}
|
|
}
|
|
} else {
|
|
l_new = alloc_htab_elem(htab, key, value, key_size,
|
|
hash, true, onallcpus);
|
|
if (!l_new) {
|
|
ret = -ENOMEM;
|
|
goto err;
|
|
}
|
|
hlist_add_head_rcu(&l_new->hash_node, head);
|
|
atomic_inc(&htab->count);
|
|
}
|
|
ret = 0;
|
|
err:
|
|
raw_spin_unlock_irqrestore(&b->lock, flags);
|
|
return ret;
|
|
}
|
|
|
|
static int htab_percpu_map_update_elem(struct bpf_map *map, void *key,
|
|
void *value, u64 map_flags)
|
|
{
|
|
return __htab_percpu_map_update_elem(map, key, value, map_flags, false);
|
|
}
|
|
|
|
/* Called from syscall or from eBPF program */
|
|
static int htab_map_delete_elem(struct bpf_map *map, void *key)
|
|
{
|
|
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
|
|
bool percpu = map->map_type == BPF_MAP_TYPE_PERCPU_HASH;
|
|
struct hlist_head *head;
|
|
struct bucket *b;
|
|
struct htab_elem *l;
|
|
unsigned long flags;
|
|
u32 hash, key_size;
|
|
int ret = -ENOENT;
|
|
|
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
|
|
|
key_size = map->key_size;
|
|
|
|
hash = htab_map_hash(key, key_size);
|
|
b = __select_bucket(htab, hash);
|
|
head = &b->head;
|
|
|
|
raw_spin_lock_irqsave(&b->lock, flags);
|
|
|
|
l = lookup_elem_raw(head, hash, key, key_size);
|
|
|
|
if (l) {
|
|
hlist_del_rcu(&l->hash_node);
|
|
atomic_dec(&htab->count);
|
|
free_htab_elem(l, percpu, key_size);
|
|
ret = 0;
|
|
}
|
|
|
|
raw_spin_unlock_irqrestore(&b->lock, flags);
|
|
return ret;
|
|
}
|
|
|
|
static void delete_all_elements(struct bpf_htab *htab)
|
|
{
|
|
int i;
|
|
|
|
for (i = 0; i < htab->n_buckets; i++) {
|
|
struct hlist_head *head = select_bucket(htab, i);
|
|
struct hlist_node *n;
|
|
struct htab_elem *l;
|
|
|
|
hlist_for_each_entry_safe(l, n, head, hash_node) {
|
|
hlist_del_rcu(&l->hash_node);
|
|
atomic_dec(&htab->count);
|
|
if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH) {
|
|
l->key_size = htab->map.key_size;
|
|
htab_percpu_elem_free(l);
|
|
} else {
|
|
kfree(l);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Called when map->refcnt goes to zero, either from workqueue or from syscall */
|
|
static void htab_map_free(struct bpf_map *map)
|
|
{
|
|
struct bpf_htab *htab = container_of(map, struct bpf_htab, map);
|
|
|
|
/* at this point bpf_prog->aux->refcnt == 0 and this map->refcnt == 0,
|
|
* so the programs (can be more than one that used this map) were
|
|
* disconnected from events. Wait for outstanding critical sections in
|
|
* these programs to complete
|
|
*/
|
|
synchronize_rcu();
|
|
|
|
/* some of kfree_rcu() callbacks for elements of this map may not have
|
|
* executed. It's ok. Proceed to free residual elements and map itself
|
|
*/
|
|
delete_all_elements(htab);
|
|
kvfree(htab->buckets);
|
|
kfree(htab);
|
|
}
|
|
|
|
static const struct bpf_map_ops htab_ops = {
|
|
.map_alloc = htab_map_alloc,
|
|
.map_free = htab_map_free,
|
|
.map_get_next_key = htab_map_get_next_key,
|
|
.map_lookup_elem = htab_map_lookup_elem,
|
|
.map_update_elem = htab_map_update_elem,
|
|
.map_delete_elem = htab_map_delete_elem,
|
|
};
|
|
|
|
static struct bpf_map_type_list htab_type __read_mostly = {
|
|
.ops = &htab_ops,
|
|
.type = BPF_MAP_TYPE_HASH,
|
|
};
|
|
|
|
/* Called from eBPF program */
|
|
static void *htab_percpu_map_lookup_elem(struct bpf_map *map, void *key)
|
|
{
|
|
struct htab_elem *l = __htab_map_lookup_elem(map, key);
|
|
|
|
if (l)
|
|
return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size));
|
|
else
|
|
return NULL;
|
|
}
|
|
|
|
int bpf_percpu_hash_copy(struct bpf_map *map, void *key, void *value)
|
|
{
|
|
struct htab_elem *l;
|
|
void __percpu *pptr;
|
|
int ret = -ENOENT;
|
|
int cpu, off = 0;
|
|
u32 size;
|
|
|
|
/* per_cpu areas are zero-filled and bpf programs can only
|
|
* access 'value_size' of them, so copying rounded areas
|
|
* will not leak any kernel data
|
|
*/
|
|
size = round_up(map->value_size, 8);
|
|
rcu_read_lock();
|
|
l = __htab_map_lookup_elem(map, key);
|
|
if (!l)
|
|
goto out;
|
|
pptr = htab_elem_get_ptr(l, map->key_size);
|
|
for_each_possible_cpu(cpu) {
|
|
bpf_long_memcpy(value + off,
|
|
per_cpu_ptr(pptr, cpu), size);
|
|
off += size;
|
|
}
|
|
ret = 0;
|
|
out:
|
|
rcu_read_unlock();
|
|
return ret;
|
|
}
|
|
|
|
int bpf_percpu_hash_update(struct bpf_map *map, void *key, void *value,
|
|
u64 map_flags)
|
|
{
|
|
return __htab_percpu_map_update_elem(map, key, value, map_flags, true);
|
|
}
|
|
|
|
static const struct bpf_map_ops htab_percpu_ops = {
|
|
.map_alloc = htab_map_alloc,
|
|
.map_free = htab_map_free,
|
|
.map_get_next_key = htab_map_get_next_key,
|
|
.map_lookup_elem = htab_percpu_map_lookup_elem,
|
|
.map_update_elem = htab_percpu_map_update_elem,
|
|
.map_delete_elem = htab_map_delete_elem,
|
|
};
|
|
|
|
static struct bpf_map_type_list htab_percpu_type __read_mostly = {
|
|
.ops = &htab_percpu_ops,
|
|
.type = BPF_MAP_TYPE_PERCPU_HASH,
|
|
};
|
|
|
|
static int __init register_htab_map(void)
|
|
{
|
|
bpf_register_map_type(&htab_type);
|
|
bpf_register_map_type(&htab_percpu_type);
|
|
return 0;
|
|
}
|
|
late_initcall(register_htab_map);
|