diff options
Diffstat (limited to '')
| -rw-r--r-- | kernel/bpf/hashtab.c | 2140 |
1 files changed, 2140 insertions, 0 deletions
diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c new file mode 100644 index 000000000..0ce445aad --- /dev/null +++ b/kernel/bpf/hashtab.c @@ -0,0 +1,2140 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com + * Copyright (c) 2016 Facebook + */ +#include <linux/bpf.h> +#include <linux/btf.h> +#include <linux/jhash.h> +#include <linux/filter.h> +#include <linux/rculist_nulls.h> +#include <linux/random.h> +#include <uapi/linux/btf.h> +#include <linux/rcupdate_trace.h> +#include "percpu_freelist.h" +#include "bpf_lru_list.h" +#include "map_in_map.h" + +#define HTAB_CREATE_FLAG_MASK \ + (BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE | \ + BPF_F_ACCESS_MASK | BPF_F_ZERO_SEED) + +#define BATCH_OPS(_name) \ + .map_lookup_batch = \ + _name##_map_lookup_batch, \ + .map_lookup_and_delete_batch = \ + _name##_map_lookup_and_delete_batch, \ + .map_update_batch = \ + generic_map_update_batch, \ + .map_delete_batch = \ + generic_map_delete_batch + +/* + * The bucket lock has two protection scopes: + * + * 1) Serializing concurrent operations from BPF programs on differrent + * CPUs + * + * 2) Serializing concurrent operations from BPF programs and sys_bpf() + * + * BPF programs can execute in any context including perf, kprobes and + * tracing. As there are almost no limits where perf, kprobes and tracing + * can be invoked from the lock operations need to be protected against + * deadlocks. Deadlocks can be caused by recursion and by an invocation in + * the lock held section when functions which acquire this lock are invoked + * from sys_bpf(). BPF recursion is prevented by incrementing the per CPU + * variable bpf_prog_active, which prevents BPF programs attached to perf + * events, kprobes and tracing to be invoked before the prior invocation + * from one of these contexts completed. sys_bpf() uses the same mechanism + * by pinning the task to the current CPU and incrementing the recursion + * protection accross the map operation. + * + * This has subtle implications on PREEMPT_RT. PREEMPT_RT forbids certain + * operations like memory allocations (even with GFP_ATOMIC) from atomic + * contexts. This is required because even with GFP_ATOMIC the memory + * allocator calls into code pathes which acquire locks with long held lock + * sections. To ensure the deterministic behaviour these locks are regular + * spinlocks, which are converted to 'sleepable' spinlocks on RT. The only + * true atomic contexts on an RT kernel are the low level hardware + * handling, scheduling, low level interrupt handling, NMIs etc. None of + * these contexts should ever do memory allocations. + * + * As regular device interrupt handlers and soft interrupts are forced into + * thread context, the existing code which does + * spin_lock*(); alloc(GPF_ATOMIC); spin_unlock*(); + * just works. + * + * In theory the BPF locks could be converted to regular spinlocks as well, + * but the bucket locks and percpu_freelist locks can be taken from + * arbitrary contexts (perf, kprobes, tracepoints) which are required to be + * atomic contexts even on RT. These mechanisms require preallocated maps, + * so there is no need to invoke memory allocations within the lock held + * sections. + * + * BPF maps which need dynamic allocation are only used from (forced) + * thread context on RT and can therefore use regular spinlocks which in + * turn allows to invoke memory allocations from the lock held section. + * + * On a non RT kernel this distinction is neither possible nor required. + * spinlock maps to raw_spinlock and the extra code is optimized out by the + * compiler. + */ +struct bucket { + struct hlist_nulls_head head; + union { + raw_spinlock_t raw_lock; + spinlock_t lock; + }; +}; + +struct bpf_htab { + struct bpf_map map; + struct bucket *buckets; + void *elems; + union { + struct pcpu_freelist freelist; + struct bpf_lru lru; + }; + struct htab_elem *__percpu *extra_elems; + 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 */ + u32 hashrnd; +}; + +/* each htab element is struct htab_elem + key + value */ +struct htab_elem { + union { + struct hlist_nulls_node hash_node; + struct { + void *padding; + union { + struct bpf_htab *htab; + struct pcpu_freelist_node fnode; + struct htab_elem *batch_flink; + }; + }; + }; + union { + struct rcu_head rcu; + struct bpf_lru_node lru_node; + }; + u32 hash; + char key[] __aligned(8); +}; + +static inline bool htab_is_prealloc(const struct bpf_htab *htab) +{ + return !(htab->map.map_flags & BPF_F_NO_PREALLOC); +} + +static inline bool htab_use_raw_lock(const struct bpf_htab *htab) +{ + return (!IS_ENABLED(CONFIG_PREEMPT_RT) || htab_is_prealloc(htab)); +} + +static void htab_init_buckets(struct bpf_htab *htab) +{ + unsigned i; + + for (i = 0; i < htab->n_buckets; i++) { + INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i); + if (htab_use_raw_lock(htab)) + raw_spin_lock_init(&htab->buckets[i].raw_lock); + else + spin_lock_init(&htab->buckets[i].lock); + } +} + +static inline unsigned long htab_lock_bucket(const struct bpf_htab *htab, + struct bucket *b) +{ + unsigned long flags; + + if (htab_use_raw_lock(htab)) + raw_spin_lock_irqsave(&b->raw_lock, flags); + else + spin_lock_irqsave(&b->lock, flags); + return flags; +} + +static inline void htab_unlock_bucket(const struct bpf_htab *htab, + struct bucket *b, + unsigned long flags) +{ + if (htab_use_raw_lock(htab)) + raw_spin_unlock_irqrestore(&b->raw_lock, flags); + else + spin_unlock_irqrestore(&b->lock, flags); +} + +static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node); + +static bool htab_is_lru(const struct bpf_htab *htab) +{ + return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH || + htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH; +} + +static bool htab_is_percpu(const struct bpf_htab *htab) +{ + return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH || + htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH; +} + +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 *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l) +{ + return *(void **)(l->key + roundup(map->key_size, 8)); +} + +static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i) +{ + return (struct htab_elem *) (htab->elems + i * htab->elem_size); +} + +static void htab_free_elems(struct bpf_htab *htab) +{ + int i; + + if (!htab_is_percpu(htab)) + goto free_elems; + + for (i = 0; i < htab->map.max_entries; i++) { + void __percpu *pptr; + + pptr = htab_elem_get_ptr(get_htab_elem(htab, i), + htab->map.key_size); + free_percpu(pptr); + cond_resched(); + } +free_elems: + bpf_map_area_free(htab->elems); +} + +/* The LRU list has a lock (lru_lock). Each htab bucket has a lock + * (bucket_lock). If both locks need to be acquired together, the lock + * order is always lru_lock -> bucket_lock and this only happens in + * bpf_lru_list.c logic. For example, certain code path of + * bpf_lru_pop_free(), which is called by function prealloc_lru_pop(), + * will acquire lru_lock first followed by acquiring bucket_lock. + * + * In hashtab.c, to avoid deadlock, lock acquisition of + * bucket_lock followed by lru_lock is not allowed. In such cases, + * bucket_lock needs to be released first before acquiring lru_lock. + */ +static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key, + u32 hash) +{ + struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash); + struct htab_elem *l; + + if (node) { + l = container_of(node, struct htab_elem, lru_node); + memcpy(l->key, key, htab->map.key_size); + return l; + } + + return NULL; +} + +static int prealloc_init(struct bpf_htab *htab) +{ + u32 num_entries = htab->map.max_entries; + int err = -ENOMEM, i; + + if (!htab_is_percpu(htab) && !htab_is_lru(htab)) + num_entries += num_possible_cpus(); + + htab->elems = bpf_map_area_alloc(htab->elem_size * num_entries, + htab->map.numa_node); + if (!htab->elems) + return -ENOMEM; + + if (!htab_is_percpu(htab)) + goto skip_percpu_elems; + + for (i = 0; i < num_entries; i++) { + u32 size = round_up(htab->map.value_size, 8); + void __percpu *pptr; + + pptr = __alloc_percpu_gfp(size, 8, GFP_USER | __GFP_NOWARN); + if (!pptr) + goto free_elems; + htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size, + pptr); + cond_resched(); + } + +skip_percpu_elems: + if (htab_is_lru(htab)) + err = bpf_lru_init(&htab->lru, + htab->map.map_flags & BPF_F_NO_COMMON_LRU, + offsetof(struct htab_elem, hash) - + offsetof(struct htab_elem, lru_node), + htab_lru_map_delete_node, + htab); + else + err = pcpu_freelist_init(&htab->freelist); + + if (err) + goto free_elems; + + if (htab_is_lru(htab)) + bpf_lru_populate(&htab->lru, htab->elems, + offsetof(struct htab_elem, lru_node), + htab->elem_size, num_entries); + else + pcpu_freelist_populate(&htab->freelist, + htab->elems + offsetof(struct htab_elem, fnode), + htab->elem_size, num_entries); + + return 0; + +free_elems: + htab_free_elems(htab); + return err; +} + +static void prealloc_destroy(struct bpf_htab *htab) +{ + htab_free_elems(htab); + + if (htab_is_lru(htab)) + bpf_lru_destroy(&htab->lru); + else + pcpu_freelist_destroy(&htab->freelist); +} + +static int alloc_extra_elems(struct bpf_htab *htab) +{ + struct htab_elem *__percpu *pptr, *l_new; + struct pcpu_freelist_node *l; + int cpu; + + pptr = __alloc_percpu_gfp(sizeof(struct htab_elem *), 8, + GFP_USER | __GFP_NOWARN); + if (!pptr) + return -ENOMEM; + + for_each_possible_cpu(cpu) { + l = pcpu_freelist_pop(&htab->freelist); + /* pop will succeed, since prealloc_init() + * preallocated extra num_possible_cpus elements + */ + l_new = container_of(l, struct htab_elem, fnode); + *per_cpu_ptr(pptr, cpu) = l_new; + } + htab->extra_elems = pptr; + return 0; +} + +/* Called from syscall */ +static int htab_map_alloc_check(union bpf_attr *attr) +{ + bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH || + attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH); + bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH || + attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH); + /* percpu_lru means each cpu has its own LRU list. + * it is different from BPF_MAP_TYPE_PERCPU_HASH where + * the map's value itself is percpu. percpu_lru has + * nothing to do with the map's value. + */ + bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU); + bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC); + bool zero_seed = (attr->map_flags & BPF_F_ZERO_SEED); + int numa_node = bpf_map_attr_numa_node(attr); + + BUILD_BUG_ON(offsetof(struct htab_elem, htab) != + offsetof(struct htab_elem, hash_node.pprev)); + BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) != + offsetof(struct htab_elem, hash_node.pprev)); + + if (lru && !bpf_capable()) + /* LRU implementation is much complicated than other + * maps. Hence, limit to CAP_BPF. + */ + return -EPERM; + + if (zero_seed && !capable(CAP_SYS_ADMIN)) + /* Guard against local DoS, and discourage production use. */ + return -EPERM; + + if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK || + !bpf_map_flags_access_ok(attr->map_flags)) + return -EINVAL; + + if (!lru && percpu_lru) + return -EINVAL; + + if (lru && !prealloc) + return -ENOTSUPP; + + if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru)) + return -EINVAL; + + /* check sanity of attributes. + * value_size == 0 may be allowed in the future to use map as a set + */ + if (attr->max_entries == 0 || attr->key_size == 0 || + attr->value_size == 0) + return -EINVAL; + + if (attr->key_size > MAX_BPF_STACK) + /* eBPF programs initialize keys on stack, so they cannot be + * larger than max stack size + */ + return -E2BIG; + + if (attr->value_size >= KMALLOC_MAX_SIZE - + 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() + */ + return -E2BIG; + + return 0; +} + +static struct bpf_map *htab_map_alloc(union bpf_attr *attr) +{ + bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH || + attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH); + bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH || + attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH); + /* percpu_lru means each cpu has its own LRU list. + * it is different from BPF_MAP_TYPE_PERCPU_HASH where + * the map's value itself is percpu. percpu_lru has + * nothing to do with the map's value. + */ + bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU); + bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC); + struct bpf_htab *htab; + u64 cost; + int err; + + htab = kzalloc(sizeof(*htab), GFP_USER); + if (!htab) + return ERR_PTR(-ENOMEM); + + bpf_map_init_from_attr(&htab->map, attr); + + if (percpu_lru) { + /* ensure each CPU's lru list has >=1 elements. + * since we are at it, make each lru list has the same + * number of elements. + */ + htab->map.max_entries = roundup(attr->max_entries, + num_possible_cpus()); + if (htab->map.max_entries < attr->max_entries) + htab->map.max_entries = rounddown(attr->max_entries, + num_possible_cpus()); + } + + /* hash table size must be power of 2 */ + htab->n_buckets = roundup_pow_of_two(htab->map.max_entries); + + 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 += round_up(htab->map.value_size, 8); + + err = -E2BIG; + /* 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; + else + cost += (u64) htab->elem_size * num_possible_cpus(); + + /* if map size is larger than memlock limit, reject it */ + err = bpf_map_charge_init(&htab->map.memory, cost); + if (err) + goto free_htab; + + err = -ENOMEM; + htab->buckets = bpf_map_area_alloc(htab->n_buckets * + sizeof(struct bucket), + htab->map.numa_node); + if (!htab->buckets) + goto free_charge; + + if (htab->map.map_flags & BPF_F_ZERO_SEED) + htab->hashrnd = 0; + else + htab->hashrnd = get_random_int(); + + htab_init_buckets(htab); + + if (prealloc) { + err = prealloc_init(htab); + if (err) + goto free_buckets; + + if (!percpu && !lru) { + /* lru itself can remove the least used element, so + * there is no need for an extra elem during map_update. + */ + err = alloc_extra_elems(htab); + if (err) + goto free_prealloc; + } + } + + return &htab->map; + +free_prealloc: + prealloc_destroy(htab); +free_buckets: + bpf_map_area_free(htab->buckets); +free_charge: + bpf_map_charge_finish(&htab->map.memory); +free_htab: + kfree(htab); + return ERR_PTR(err); +} + +static inline u32 htab_map_hash(const void *key, u32 key_len, u32 hashrnd) +{ + return jhash(key, key_len, hashrnd); +} + +static inline struct bucket *__select_bucket(struct bpf_htab *htab, u32 hash) +{ + return &htab->buckets[hash & (htab->n_buckets - 1)]; +} + +static inline struct hlist_nulls_head *select_bucket(struct bpf_htab *htab, u32 hash) +{ + return &__select_bucket(htab, hash)->head; +} + +/* this lookup function can only be called with bucket lock taken */ +static struct htab_elem *lookup_elem_raw(struct hlist_nulls_head *head, u32 hash, + void *key, u32 key_size) +{ + struct hlist_nulls_node *n; + struct htab_elem *l; + + hlist_nulls_for_each_entry_rcu(l, n, head, hash_node) + if (l->hash == hash && !memcmp(&l->key, key, key_size)) + return l; + + return NULL; +} + +/* can be called without bucket lock. it will repeat the loop in + * the unlikely event when elements moved from one bucket into another + * while link list is being walked + */ +static struct htab_elem *lookup_nulls_elem_raw(struct hlist_nulls_head *head, + u32 hash, void *key, + u32 key_size, u32 n_buckets) +{ + struct hlist_nulls_node *n; + struct htab_elem *l; + +again: + hlist_nulls_for_each_entry_rcu(l, n, head, hash_node) + if (l->hash == hash && !memcmp(&l->key, key, key_size)) + return l; + + if (unlikely(get_nulls_value(n) != (hash & (n_buckets - 1)))) + goto again; + + return NULL; +} + +/* Called from syscall or from eBPF program directly, so + * arguments have to match bpf_map_lookup_elem() exactly. + * The return value is adjusted by BPF instructions + * in htab_map_gen_lookup(). + */ +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_nulls_head *head; + struct htab_elem *l; + u32 hash, key_size; + + WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held()); + + key_size = map->key_size; + + hash = htab_map_hash(key, key_size, htab->hashrnd); + + head = select_bucket(htab, hash); + + l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets); + + 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; +} + +/* inline bpf_map_lookup_elem() call. + * Instead of: + * bpf_prog + * bpf_map_lookup_elem + * map->ops->map_lookup_elem + * htab_map_lookup_elem + * __htab_map_lookup_elem + * do: + * bpf_prog + * __htab_map_lookup_elem + */ +static int htab_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf) +{ + struct bpf_insn *insn = insn_buf; + const int ret = BPF_REG_0; + + BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem, + (void *(*)(struct bpf_map *map, void *key))NULL)); + *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem)); + *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 1); + *insn++ = BPF_ALU64_IMM(BPF_ADD, ret, + offsetof(struct htab_elem, key) + + round_up(map->key_size, 8)); + return insn - insn_buf; +} + +static __always_inline void *__htab_lru_map_lookup_elem(struct bpf_map *map, + void *key, const bool mark) +{ + struct htab_elem *l = __htab_map_lookup_elem(map, key); + + if (l) { + if (mark) + bpf_lru_node_set_ref(&l->lru_node); + return l->key + round_up(map->key_size, 8); + } + + return NULL; +} + +static void *htab_lru_map_lookup_elem(struct bpf_map *map, void *key) +{ + return __htab_lru_map_lookup_elem(map, key, true); +} + +static void *htab_lru_map_lookup_elem_sys(struct bpf_map *map, void *key) +{ + return __htab_lru_map_lookup_elem(map, key, false); +} + +static int htab_lru_map_gen_lookup(struct bpf_map *map, + struct bpf_insn *insn_buf) +{ + struct bpf_insn *insn = insn_buf; + const int ret = BPF_REG_0; + const int ref_reg = BPF_REG_1; + + BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem, + (void *(*)(struct bpf_map *map, void *key))NULL)); + *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem)); + *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 4); + *insn++ = BPF_LDX_MEM(BPF_B, ref_reg, ret, + offsetof(struct htab_elem, lru_node) + + offsetof(struct bpf_lru_node, ref)); + *insn++ = BPF_JMP_IMM(BPF_JNE, ref_reg, 0, 1); + *insn++ = BPF_ST_MEM(BPF_B, ret, + offsetof(struct htab_elem, lru_node) + + offsetof(struct bpf_lru_node, ref), + 1); + *insn++ = BPF_ALU64_IMM(BPF_ADD, ret, + offsetof(struct htab_elem, key) + + round_up(map->key_size, 8)); + return insn - insn_buf; +} + +/* It is called from the bpf_lru_list when the LRU needs to delete + * older elements from the htab. + */ +static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node) +{ + struct bpf_htab *htab = (struct bpf_htab *)arg; + struct htab_elem *l = NULL, *tgt_l; + struct hlist_nulls_head *head; + struct hlist_nulls_node *n; + unsigned long flags; + struct bucket *b; + + tgt_l = container_of(node, struct htab_elem, lru_node); + b = __select_bucket(htab, tgt_l->hash); + head = &b->head; + + flags = htab_lock_bucket(htab, b); + + hlist_nulls_for_each_entry_rcu(l, n, head, hash_node) + if (l == tgt_l) { + hlist_nulls_del_rcu(&l->hash_node); + break; + } + + htab_unlock_bucket(htab, b, flags); + + return l == tgt_l; +} + +/* 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_nulls_head *head; + struct htab_elem *l, *next_l; + u32 hash, key_size; + int i = 0; + + WARN_ON_ONCE(!rcu_read_lock_held()); + + key_size = map->key_size; + + if (!key) + goto find_first_elem; + + hash = htab_map_hash(key, key_size, htab->hashrnd); + + head = select_bucket(htab, hash); + + /* lookup the key */ + l = lookup_nulls_elem_raw(head, hash, key, key_size, htab->n_buckets); + + if (!l) + goto find_first_elem; + + /* key was found, get next key in the same bucket */ + next_l = hlist_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_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_nulls_entry_safe(rcu_dereference_raw(hlist_nulls_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; + } + } + + /* iterated over all buckets and all elements */ + return -ENOENT; +} + +static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l) +{ + if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH) + free_percpu(htab_elem_get_ptr(l, htab->map.key_size)); + kfree(l); +} + +static void htab_elem_free_rcu(struct rcu_head *head) +{ + struct htab_elem *l = container_of(head, struct htab_elem, rcu); + struct bpf_htab *htab = l->htab; + + htab_elem_free(htab, l); +} + +static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l) +{ + struct bpf_map *map = &htab->map; + void *ptr; + + if (map->ops->map_fd_put_ptr) { + ptr = fd_htab_map_get_ptr(map, l); + map->ops->map_fd_put_ptr(ptr); + } +} + +static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l) +{ + htab_put_fd_value(htab, l); + + if (htab_is_prealloc(htab)) { + __pcpu_freelist_push(&htab->freelist, &l->fnode); + } else { + atomic_dec(&htab->count); + l->htab = htab; + call_rcu(&l->rcu, htab_elem_free_rcu); + } +} + +static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr, + void *value, bool onallcpus) +{ + if (!onallcpus) { + /* copy true value_size bytes */ + memcpy(this_cpu_ptr(pptr), value, htab->map.value_size); + } else { + u32 size = round_up(htab->map.value_size, 8); + int off = 0, cpu; + + for_each_possible_cpu(cpu) { + bpf_long_memcpy(per_cpu_ptr(pptr, cpu), + value + off, size); + off += size; + } + } +} + +static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr, + void *value, bool onallcpus) +{ + /* When using prealloc and not setting the initial value on all cpus, + * zero-fill element values for other cpus (just as what happens when + * not using prealloc). Otherwise, bpf program has no way to ensure + * known initial values for cpus other than current one + * (onallcpus=false always when coming from bpf prog). + */ + if (htab_is_prealloc(htab) && !onallcpus) { + u32 size = round_up(htab->map.value_size, 8); + int current_cpu = raw_smp_processor_id(); + int cpu; + + for_each_possible_cpu(cpu) { + if (cpu == current_cpu) + bpf_long_memcpy(per_cpu_ptr(pptr, cpu), value, + size); + else + memset(per_cpu_ptr(pptr, cpu), 0, size); + } + } else { + pcpu_copy_value(htab, pptr, value, onallcpus); + } +} + +static bool fd_htab_map_needs_adjust(const struct bpf_htab *htab) +{ + return htab->map.map_type == BPF_MAP_TYPE_HASH_OF_MAPS && + BITS_PER_LONG == 64; +} + +static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key, + void *value, u32 key_size, u32 hash, + bool percpu, bool onallcpus, + struct htab_elem *old_elem) +{ + u32 size = htab->map.value_size; + bool prealloc = htab_is_prealloc(htab); + struct htab_elem *l_new, **pl_new; + void __percpu *pptr; + + if (prealloc) { + if (old_elem) { + /* if we're updating the existing element, + * use per-cpu extra elems to avoid freelist_pop/push + */ + pl_new = this_cpu_ptr(htab->extra_elems); + l_new = *pl_new; + htab_put_fd_value(htab, old_elem); + *pl_new = old_elem; + } else { + struct pcpu_freelist_node *l; + + l = __pcpu_freelist_pop(&htab->freelist); + if (!l) + return ERR_PTR(-E2BIG); + l_new = container_of(l, struct htab_elem, fnode); + } + } else { + if (atomic_inc_return(&htab->count) > htab->map.max_entries) + if (!old_elem) { + /* when map is full and update() is replacing + * old element, it's ok to allocate, since + * old element will be freed immediately. + * Otherwise return an error + */ + l_new = ERR_PTR(-E2BIG); + goto dec_count; + } + l_new = kmalloc_node(htab->elem_size, GFP_ATOMIC | __GFP_NOWARN, + htab->map.numa_node); + if (!l_new) { + l_new = ERR_PTR(-ENOMEM); + goto dec_count; + } + check_and_init_map_lock(&htab->map, + l_new->key + round_up(key_size, 8)); + } + + memcpy(l_new->key, key, key_size); + if (percpu) { + size = round_up(size, 8); + if (prealloc) { + pptr = htab_elem_get_ptr(l_new, key_size); + } else { + /* alloc_percpu zero-fills */ + pptr = __alloc_percpu_gfp(size, 8, + GFP_ATOMIC | __GFP_NOWARN); + if (!pptr) { + kfree(l_new); + l_new = ERR_PTR(-ENOMEM); + goto dec_count; + } + } + + pcpu_init_value(htab, pptr, value, onallcpus); + + if (!prealloc) + htab_elem_set_ptr(l_new, key_size, pptr); + } else if (fd_htab_map_needs_adjust(htab)) { + size = round_up(size, 8); + memcpy(l_new->key + round_up(key_size, 8), value, size); + } else { + copy_map_value(&htab->map, + l_new->key + round_up(key_size, 8), + value); + } + + l_new->hash = hash; + return l_new; +dec_count: + atomic_dec(&htab->count); + return l_new; +} + +static int check_flags(struct bpf_htab *htab, struct htab_elem *l_old, + u64 map_flags) +{ + if (l_old && (map_flags & ~BPF_F_LOCK) == BPF_NOEXIST) + /* elem already exists */ + return -EEXIST; + + if (!l_old && (map_flags & ~BPF_F_LOCK) == 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_nulls_head *head; + unsigned long flags; + struct bucket *b; + u32 key_size, hash; + int ret; + + if (unlikely((map_flags & ~BPF_F_LOCK) > BPF_EXIST)) + /* unknown flags */ + return -EINVAL; + + WARN_ON_ONCE(!rcu_read_lock_held() && !rcu_read_lock_trace_held()); + + key_size = map->key_size; + + hash = htab_map_hash(key, key_size, htab->hashrnd); + + b = __select_bucket(htab, hash); + head = &b->head; + + if (unlikely(map_flags & BPF_F_LOCK)) { + if (unlikely(!map_value_has_spin_lock(map))) + return -EINVAL; + /* find an element without taking the bucket lock */ + l_old = lookup_nulls_elem_raw(head, hash, key, key_size, + htab->n_buckets); + ret = check_flags(htab, l_old, map_flags); + if (ret) + return ret; + if (l_old) { + /* grab the element lock and update value in place */ + copy_map_value_locked(map, + l_old->key + round_up(key_size, 8), + value, false); + return 0; + } + /* fall through, grab the bucket lock and lookup again. + * 99.9% chance that the element won't be found, + * but second lookup under lock has to be done. + */ + } + + flags = htab_lock_bucket(htab, b); + + l_old = lookup_elem_raw(head, hash, key, key_size); + + ret = check_flags(htab, l_old, map_flags); + if (ret) + goto err; + + if (unlikely(l_old && (map_flags & BPF_F_LOCK))) { + /* first lookup without the bucket lock didn't find the element, + * but second lookup with the bucket lock found it. + * This case is highly unlikely, but has to be dealt with: + * grab the element lock in addition to the bucket lock + * and update element in place + */ + copy_map_value_locked(map, + l_old->key + round_up(key_size, 8), + value, false); + ret = 0; + goto err; + } + + l_new = alloc_htab_elem(htab, key, value, key_size, hash, false, false, + l_old); + if (IS_ERR(l_new)) { + /* all pre-allocated elements are in use or memory exhausted */ + ret = PTR_ERR(l_new); + goto err; + } + + /* add new element to the head of the list, so that + * concurrent search will find it before old elem + */ + hlist_nulls_add_head_rcu(&l_new->hash_node, head); + if (l_old) { + hlist_nulls_del_rcu(&l_old->hash_node); + if (!htab_is_prealloc(htab)) + free_htab_elem(htab, l_old); + } + ret = 0; +err: + htab_unlock_bucket(htab, b, flags); + return ret; +} + +static int htab_lru_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, *l_old = NULL; + struct hlist_nulls_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() && !rcu_read_lock_trace_held()); + + key_size = map->key_size; + + hash = htab_map_hash(key, key_size, htab->hashrnd); + + b = __select_bucket(htab, hash); + head = &b->head; + + /* For LRU, we need to alloc before taking bucket's + * spinlock because getting free nodes from LRU may need + * to remove older elements from htab and this removal + * operation will need a bucket lock. + */ + l_new = prealloc_lru_pop(htab, key, hash); + if (!l_new) + return -ENOMEM; + memcpy(l_new->key + round_up(map->key_size, 8), value, map->value_size); + + flags = htab_lock_bucket(htab, b); + + 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_nulls_add_head_rcu(&l_new->hash_node, head); + if (l_old) { + bpf_lru_node_set_ref(&l_new->lru_node); + hlist_nulls_del_rcu(&l_old->hash_node); + } + ret = 0; + +err: + htab_unlock_bucket(htab, b, flags); + + if (ret) + bpf_lru_push_free(&htab->lru, &l_new->lru_node); + else if (l_old) + bpf_lru_push_free(&htab->lru, &l_old->lru_node); + + 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_nulls_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, htab->hashrnd); + + b = __select_bucket(htab, hash); + head = &b->head; + + flags = htab_lock_bucket(htab, b); + + 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) { + /* per-cpu hash map can update value in-place */ + pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size), + value, onallcpus); + } else { + l_new = alloc_htab_elem(htab, key, value, key_size, + hash, true, onallcpus, NULL); + if (IS_ERR(l_new)) { + ret = PTR_ERR(l_new); + goto err; + } + hlist_nulls_add_head_rcu(&l_new->hash_node, head); + } + ret = 0; +err: + htab_unlock_bucket(htab, b, flags); + return ret; +} + +static int __htab_lru_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_nulls_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, htab->hashrnd); + + b = __select_bucket(htab, hash); + head = &b->head; + + /* For LRU, we need to alloc before taking bucket's + * spinlock because LRU's elem alloc may need + * to remove older elem from htab and this removal + * operation will need a bucket lock. + */ + if (map_flags != BPF_EXIST) { + l_new = prealloc_lru_pop(htab, key, hash); + if (!l_new) + return -ENOMEM; + } + + flags = htab_lock_bucket(htab, b); + + 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) { + bpf_lru_node_set_ref(&l_old->lru_node); + + /* per-cpu hash map can update value in-place */ + pcpu_copy_value(htab, htab_elem_get_ptr(l_old, key_size), + value, onallcpus); + } else { + pcpu_init_value(htab, htab_elem_get_ptr(l_new, key_size), + value, onallcpus); + hlist_nulls_add_head_rcu(&l_new->hash_node, head); + l_new = NULL; + } + ret = 0; +err: + htab_unlock_bucket(htab, b, flags); + if (l_new) + bpf_lru_push_free(&htab->lru, &l_new->lru_node); + 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); +} + +static int htab_lru_percpu_map_update_elem(struct bpf_map *map, void *key, + void *value, u64 map_flags) +{ + return __htab_lru_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); + struct hlist_nulls_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() && !rcu_read_lock_trace_held()); + + key_size = map->key_size; + + hash = htab_map_hash(key, key_size, htab->hashrnd); + b = __select_bucket(htab, hash); + head = &b->head; + + flags = htab_lock_bucket(htab, b); + + l = lookup_elem_raw(head, hash, key, key_size); + + if (l) { + hlist_nulls_del_rcu(&l->hash_node); + free_htab_elem(htab, l); + ret = 0; + } + + htab_unlock_bucket(htab, b, flags); + return ret; +} + +static int htab_lru_map_delete_elem(struct bpf_map *map, void *key) +{ + struct bpf_htab *htab = container_of(map, struct bpf_htab, map); + struct hlist_nulls_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() && !rcu_read_lock_trace_held()); + + key_size = map->key_size; + + hash = htab_map_hash(key, key_size, htab->hashrnd); + b = __select_bucket(htab, hash); + head = &b->head; + + flags = htab_lock_bucket(htab, b); + + l = lookup_elem_raw(head, hash, key, key_size); + + if (l) { + hlist_nulls_del_rcu(&l->hash_node); + ret = 0; + } + + htab_unlock_bucket(htab, b, flags); + if (l) + bpf_lru_push_free(&htab->lru, &l->lru_node); + return ret; +} + +static void delete_all_elements(struct bpf_htab *htab) +{ + int i; + + for (i = 0; i < htab->n_buckets; i++) { + struct hlist_nulls_head *head = select_bucket(htab, i); + struct hlist_nulls_node *n; + struct htab_elem *l; + + hlist_nulls_for_each_entry_safe(l, n, head, hash_node) { + hlist_nulls_del_rcu(&l->hash_node); + htab_elem_free(htab, 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); + + /* bpf_free_used_maps() or close(map_fd) will trigger this map_free callback. + * bpf_free_used_maps() is called after bpf prog is no longer executing. + * There is no need to synchronize_rcu() here to protect map elements. + */ + + /* some of free_htab_elem() callbacks for elements of this map may + * not have executed. Wait for them. + */ + rcu_barrier(); + if (!htab_is_prealloc(htab)) + delete_all_elements(htab); + else + prealloc_destroy(htab); + + free_percpu(htab->extra_elems); + bpf_map_area_free(htab->buckets); + kfree(htab); +} + +static void htab_map_seq_show_elem(struct bpf_map *map, void *key, + struct seq_file *m) +{ + void *value; + + rcu_read_lock(); + + value = htab_map_lookup_elem(map, key); + if (!value) { + rcu_read_unlock(); + return; + } + + btf_type_seq_show(map->btf, map->btf_key_type_id, key, m); + seq_puts(m, ": "); + btf_type_seq_show(map->btf, map->btf_value_type_id, value, m); + seq_puts(m, "\n"); + + rcu_read_unlock(); +} + +static int +__htab_map_lookup_and_delete_batch(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr, + bool do_delete, bool is_lru_map, + bool is_percpu) +{ + struct bpf_htab *htab = container_of(map, struct bpf_htab, map); + u32 bucket_cnt, total, key_size, value_size, roundup_key_size; + void *keys = NULL, *values = NULL, *value, *dst_key, *dst_val; + void __user *uvalues = u64_to_user_ptr(attr->batch.values); + void __user *ukeys = u64_to_user_ptr(attr->batch.keys); + void *ubatch = u64_to_user_ptr(attr->batch.in_batch); + u32 batch, max_count, size, bucket_size; + struct htab_elem *node_to_free = NULL; + u64 elem_map_flags, map_flags; + struct hlist_nulls_head *head; + struct hlist_nulls_node *n; + unsigned long flags = 0; + bool locked = false; + struct htab_elem *l; + struct bucket *b; + int ret = 0; + + elem_map_flags = attr->batch.elem_flags; + if ((elem_map_flags & ~BPF_F_LOCK) || + ((elem_map_flags & BPF_F_LOCK) && !map_value_has_spin_lock(map))) + return -EINVAL; + + map_flags = attr->batch.flags; + if (map_flags) + return -EINVAL; + + max_count = attr->batch.count; + if (!max_count) + return 0; + + if (put_user(0, &uattr->batch.count)) + return -EFAULT; + + batch = 0; + if (ubatch && copy_from_user(&batch, ubatch, sizeof(batch))) + return -EFAULT; + + if (batch >= htab->n_buckets) + return -ENOENT; + + key_size = htab->map.key_size; + roundup_key_size = round_up(htab->map.key_size, 8); + value_size = htab->map.value_size; + size = round_up(value_size, 8); + if (is_percpu) + value_size = size * num_possible_cpus(); + total = 0; + /* while experimenting with hash tables with sizes ranging from 10 to + * 1000, it was observed that a bucket can have upto 5 entries. + */ + bucket_size = 5; + +alloc: + /* We cannot do copy_from_user or copy_to_user inside + * the rcu_read_lock. Allocate enough space here. + */ + keys = kvmalloc_array(key_size, bucket_size, GFP_USER | __GFP_NOWARN); + values = kvmalloc_array(value_size, bucket_size, GFP_USER | __GFP_NOWARN); + if (!keys || !values) { + ret = -ENOMEM; + goto after_loop; + } + +again: + bpf_disable_instrumentation(); + rcu_read_lock(); +again_nocopy: + dst_key = keys; + dst_val = values; + b = &htab->buckets[batch]; + head = &b->head; + /* do not grab the lock unless need it (bucket_cnt > 0). */ + if (locked) + flags = htab_lock_bucket(htab, b); + + bucket_cnt = 0; + hlist_nulls_for_each_entry_rcu(l, n, head, hash_node) + bucket_cnt++; + + if (bucket_cnt && !locked) { + locked = true; + goto again_nocopy; + } + + if (bucket_cnt > (max_count - total)) { + if (total == 0) + ret = -ENOSPC; + /* Note that since bucket_cnt > 0 here, it is implicit + * that the locked was grabbed, so release it. + */ + htab_unlock_bucket(htab, b, flags); + rcu_read_unlock(); + bpf_enable_instrumentation(); + goto after_loop; + } + + if (bucket_cnt > bucket_size) { + bucket_size = bucket_cnt; + /* Note that since bucket_cnt > 0 here, it is implicit + * that the locked was grabbed, so release it. + */ + htab_unlock_bucket(htab, b, flags); + rcu_read_unlock(); + bpf_enable_instrumentation(); + kvfree(keys); + kvfree(values); + goto alloc; + } + + /* Next block is only safe to run if you have grabbed the lock */ + if (!locked) + goto next_batch; + + hlist_nulls_for_each_entry_safe(l, n, head, hash_node) { + memcpy(dst_key, l->key, key_size); + + if (is_percpu) { + int off = 0, cpu; + void __percpu *pptr; + + pptr = htab_elem_get_ptr(l, map->key_size); + for_each_possible_cpu(cpu) { + bpf_long_memcpy(dst_val + off, + per_cpu_ptr(pptr, cpu), size); + off += size; + } + } else { + value = l->key + roundup_key_size; + if (elem_map_flags & BPF_F_LOCK) + copy_map_value_locked(map, dst_val, value, + true); + else + copy_map_value(map, dst_val, value); + check_and_init_map_lock(map, dst_val); + } + if (do_delete) { + hlist_nulls_del_rcu(&l->hash_node); + + /* bpf_lru_push_free() will acquire lru_lock, which + * may cause deadlock. See comments in function + * prealloc_lru_pop(). Let us do bpf_lru_push_free() + * after releasing the bucket lock. + */ + if (is_lru_map) { + l->batch_flink = node_to_free; + node_to_free = l; + } else { + free_htab_elem(htab, l); + } + } + dst_key += key_size; + dst_val += value_size; + } + + htab_unlock_bucket(htab, b, flags); + locked = false; + + while (node_to_free) { + l = node_to_free; + node_to_free = node_to_free->batch_flink; + bpf_lru_push_free(&htab->lru, &l->lru_node); + } + +next_batch: + /* If we are not copying data, we can go to next bucket and avoid + * unlocking the rcu. + */ + if (!bucket_cnt && (batch + 1 < htab->n_buckets)) { + batch++; + goto again_nocopy; + } + + rcu_read_unlock(); + bpf_enable_instrumentation(); + if (bucket_cnt && (copy_to_user(ukeys + total * key_size, keys, + key_size * bucket_cnt) || + copy_to_user(uvalues + total * value_size, values, + value_size * bucket_cnt))) { + ret = -EFAULT; + goto after_loop; + } + + total += bucket_cnt; + batch++; + if (batch >= htab->n_buckets) { + ret = -ENOENT; + goto after_loop; + } + goto again; + +after_loop: + if (ret == -EFAULT) + goto out; + + /* copy # of entries and next batch */ + ubatch = u64_to_user_ptr(attr->batch.out_batch); + if (copy_to_user(ubatch, &batch, sizeof(batch)) || + put_user(total, &uattr->batch.count)) + ret = -EFAULT; + +out: + kvfree(keys); + kvfree(values); + return ret; +} + +static int +htab_percpu_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, false, + false, true); +} + +static int +htab_percpu_map_lookup_and_delete_batch(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, true, + false, true); +} + +static int +htab_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, false, + false, false); +} + +static int +htab_map_lookup_and_delete_batch(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, true, + false, false); +} + +static int +htab_lru_percpu_map_lookup_batch(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, false, + true, true); +} + +static int +htab_lru_percpu_map_lookup_and_delete_batch(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, true, + true, true); +} + +static int +htab_lru_map_lookup_batch(struct bpf_map *map, const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, false, + true, false); +} + +static int +htab_lru_map_lookup_and_delete_batch(struct bpf_map *map, + const union bpf_attr *attr, + union bpf_attr __user *uattr) +{ + return __htab_map_lookup_and_delete_batch(map, attr, uattr, true, + true, false); +} + +struct bpf_iter_seq_hash_map_info { + struct bpf_map *map; + struct bpf_htab *htab; + void *percpu_value_buf; // non-zero means percpu hash + u32 bucket_id; + u32 skip_elems; +}; + +static struct htab_elem * +bpf_hash_map_seq_find_next(struct bpf_iter_seq_hash_map_info *info, + struct htab_elem *prev_elem) +{ + const struct bpf_htab *htab = info->htab; + u32 skip_elems = info->skip_elems; + u32 bucket_id = info->bucket_id; + struct hlist_nulls_head *head; + struct hlist_nulls_node *n; + struct htab_elem *elem; + struct bucket *b; + u32 i, count; + + if (bucket_id >= htab->n_buckets) + return NULL; + + /* try to find next elem in the same bucket */ + if (prev_elem) { + /* no update/deletion on this bucket, prev_elem should be still valid + * and we won't skip elements. + */ + n = rcu_dereference_raw(hlist_nulls_next_rcu(&prev_elem->hash_node)); + elem = hlist_nulls_entry_safe(n, struct htab_elem, hash_node); + if (elem) + return elem; + + /* not found, unlock and go to the next bucket */ + b = &htab->buckets[bucket_id++]; + rcu_read_unlock(); + skip_elems = 0; + } + + for (i = bucket_id; i < htab->n_buckets; i++) { + b = &htab->buckets[i]; + rcu_read_lock(); + + count = 0; + head = &b->head; + hlist_nulls_for_each_entry_rcu(elem, n, head, hash_node) { + if (count >= skip_elems) { + info->bucket_id = i; + info->skip_elems = count; + return elem; + } + count++; + } + + rcu_read_unlock(); + skip_elems = 0; + } + + info->bucket_id = i; + info->skip_elems = 0; + return NULL; +} + +static void *bpf_hash_map_seq_start(struct seq_file *seq, loff_t *pos) +{ + struct bpf_iter_seq_hash_map_info *info = seq->private; + struct htab_elem *elem; + + elem = bpf_hash_map_seq_find_next(info, NULL); + if (!elem) + return NULL; + + if (*pos == 0) + ++*pos; + return elem; +} + +static void *bpf_hash_map_seq_next(struct seq_file *seq, void *v, loff_t *pos) +{ + struct bpf_iter_seq_hash_map_info *info = seq->private; + + ++*pos; + ++info->skip_elems; + return bpf_hash_map_seq_find_next(info, v); +} + +static int __bpf_hash_map_seq_show(struct seq_file *seq, struct htab_elem *elem) +{ + struct bpf_iter_seq_hash_map_info *info = seq->private; + u32 roundup_key_size, roundup_value_size; + struct bpf_iter__bpf_map_elem ctx = {}; + struct bpf_map *map = info->map; + struct bpf_iter_meta meta; + int ret = 0, off = 0, cpu; + struct bpf_prog *prog; + void __percpu *pptr; + + meta.seq = seq; + prog = bpf_iter_get_info(&meta, elem == NULL); + if (prog) { + ctx.meta = &meta; + ctx.map = info->map; + if (elem) { + roundup_key_size = round_up(map->key_size, 8); + ctx.key = elem->key; + if (!info->percpu_value_buf) { + ctx.value = elem->key + roundup_key_size; + } else { + roundup_value_size = round_up(map->value_size, 8); + pptr = htab_elem_get_ptr(elem, map->key_size); + for_each_possible_cpu(cpu) { + bpf_long_memcpy(info->percpu_value_buf + off, + per_cpu_ptr(pptr, cpu), + roundup_value_size); + off += roundup_value_size; + } + ctx.value = info->percpu_value_buf; + } + } + ret = bpf_iter_run_prog(prog, &ctx); + } + + return ret; +} + +static int bpf_hash_map_seq_show(struct seq_file *seq, void *v) +{ + return __bpf_hash_map_seq_show(seq, v); +} + +static void bpf_hash_map_seq_stop(struct seq_file *seq, void *v) +{ + if (!v) + (void)__bpf_hash_map_seq_show(seq, NULL); + else + rcu_read_unlock(); +} + +static int bpf_iter_init_hash_map(void *priv_data, + struct bpf_iter_aux_info *aux) +{ + struct bpf_iter_seq_hash_map_info *seq_info = priv_data; + struct bpf_map *map = aux->map; + void *value_buf; + u32 buf_size; + + if (map->map_type == BPF_MAP_TYPE_PERCPU_HASH || + map->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH) { + buf_size = round_up(map->value_size, 8) * num_possible_cpus(); + value_buf = kmalloc(buf_size, GFP_USER | __GFP_NOWARN); + if (!value_buf) + return -ENOMEM; + + seq_info->percpu_value_buf = value_buf; + } + + bpf_map_inc_with_uref(map); + seq_info->map = map; + seq_info->htab = container_of(map, struct bpf_htab, map); + return 0; +} + +static void bpf_iter_fini_hash_map(void *priv_data) +{ + struct bpf_iter_seq_hash_map_info *seq_info = priv_data; + + bpf_map_put_with_uref(seq_info->map); + kfree(seq_info->percpu_value_buf); +} + +static const struct seq_operations bpf_hash_map_seq_ops = { + .start = bpf_hash_map_seq_start, + .next = bpf_hash_map_seq_next, + .stop = bpf_hash_map_seq_stop, + .show = bpf_hash_map_seq_show, +}; + +static const struct bpf_iter_seq_info iter_seq_info = { + .seq_ops = &bpf_hash_map_seq_ops, + .init_seq_private = bpf_iter_init_hash_map, + .fini_seq_private = bpf_iter_fini_hash_map, + .seq_priv_size = sizeof(struct bpf_iter_seq_hash_map_info), +}; + +static int htab_map_btf_id; +const struct bpf_map_ops htab_map_ops = { + .map_meta_equal = bpf_map_meta_equal, + .map_alloc_check = htab_map_alloc_check, + .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, + .map_gen_lookup = htab_map_gen_lookup, + .map_seq_show_elem = htab_map_seq_show_elem, + BATCH_OPS(htab), + .map_btf_name = "bpf_htab", + .map_btf_id = &htab_map_btf_id, + .iter_seq_info = &iter_seq_info, +}; + +static int htab_lru_map_btf_id; +const struct bpf_map_ops htab_lru_map_ops = { + .map_meta_equal = bpf_map_meta_equal, + .map_alloc_check = htab_map_alloc_check, + .map_alloc = htab_map_alloc, + .map_free = htab_map_free, + .map_get_next_key = htab_map_get_next_key, + .map_lookup_elem = htab_lru_map_lookup_elem, + .map_lookup_elem_sys_only = htab_lru_map_lookup_elem_sys, + .map_update_elem = htab_lru_map_update_elem, + .map_delete_elem = htab_lru_map_delete_elem, + .map_gen_lookup = htab_lru_map_gen_lookup, + .map_seq_show_elem = htab_map_seq_show_elem, + BATCH_OPS(htab_lru), + .map_btf_name = "bpf_htab", + .map_btf_id = &htab_lru_map_btf_id, + .iter_seq_info = &iter_seq_info, +}; + +/* 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; +} + +static void *htab_lru_percpu_map_lookup_elem(struct bpf_map *map, void *key) +{ + struct htab_elem *l = __htab_map_lookup_elem(map, key); + + if (l) { + bpf_lru_node_set_ref(&l->lru_node); + return this_cpu_ptr(htab_elem_get_ptr(l, map->key_size)); + } + + 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; + /* We do not mark LRU map element here in order to not mess up + * eviction heuristics when user space does a map walk. + */ + 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) +{ + struct bpf_htab *htab = container_of(map, struct bpf_htab, map); + int ret; + + rcu_read_lock(); + if (htab_is_lru(htab)) + ret = __htab_lru_percpu_map_update_elem(map, key, value, + map_flags, true); + else + ret = __htab_percpu_map_update_elem(map, key, value, map_flags, + true); + rcu_read_unlock(); + + return ret; +} + +static void htab_percpu_map_seq_show_elem(struct bpf_map *map, void *key, + struct seq_file *m) +{ + struct htab_elem *l; + void __percpu *pptr; + int cpu; + + rcu_read_lock(); + + l = __htab_map_lookup_elem(map, key); + if (!l) { + rcu_read_unlock(); + return; + } + + btf_type_seq_show(map->btf, map->btf_key_type_id, key, m); + seq_puts(m, ": {\n"); + pptr = htab_elem_get_ptr(l, map->key_size); + for_each_possible_cpu(cpu) { + seq_printf(m, "\tcpu%d: ", cpu); + btf_type_seq_show(map->btf, map->btf_value_type_id, + per_cpu_ptr(pptr, cpu), m); + seq_puts(m, "\n"); + } + seq_puts(m, "}\n"); + + rcu_read_unlock(); +} + +static int htab_percpu_map_btf_id; +const struct bpf_map_ops htab_percpu_map_ops = { + .map_meta_equal = bpf_map_meta_equal, + .map_alloc_check = htab_map_alloc_check, + .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, + .map_seq_show_elem = htab_percpu_map_seq_show_elem, + BATCH_OPS(htab_percpu), + .map_btf_name = "bpf_htab", + .map_btf_id = &htab_percpu_map_btf_id, + .iter_seq_info = &iter_seq_info, +}; + +static int htab_lru_percpu_map_btf_id; +const struct bpf_map_ops htab_lru_percpu_map_ops = { + .map_meta_equal = bpf_map_meta_equal, + .map_alloc_check = htab_map_alloc_check, + .map_alloc = htab_map_alloc, + .map_free = htab_map_free, + .map_get_next_key = htab_map_get_next_key, + .map_lookup_elem = htab_lru_percpu_map_lookup_elem, + .map_update_elem = htab_lru_percpu_map_update_elem, + .map_delete_elem = htab_lru_map_delete_elem, + .map_seq_show_elem = htab_percpu_map_seq_show_elem, + BATCH_OPS(htab_lru_percpu), + .map_btf_name = "bpf_htab", + .map_btf_id = &htab_lru_percpu_map_btf_id, + .iter_seq_info = &iter_seq_info, +}; + +static int fd_htab_map_alloc_check(union bpf_attr *attr) +{ + if (attr->value_size != sizeof(u32)) + return -EINVAL; + return htab_map_alloc_check(attr); +} + +static void fd_htab_map_free(struct bpf_map *map) +{ + struct bpf_htab *htab = container_of(map, struct bpf_htab, map); + struct hlist_nulls_node *n; + struct hlist_nulls_head *head; + struct htab_elem *l; + int i; + + for (i = 0; i < htab->n_buckets; i++) { + head = select_bucket(htab, i); + + hlist_nulls_for_each_entry_safe(l, n, head, hash_node) { + void *ptr = fd_htab_map_get_ptr(map, l); + + map->ops->map_fd_put_ptr(ptr); + } + } + + htab_map_free(map); +} + +/* only called from syscall */ +int bpf_fd_htab_map_lookup_elem(struct bpf_map *map, void *key, u32 *value) +{ + void **ptr; + int ret = 0; + + if (!map->ops->map_fd_sys_lookup_elem) + return -ENOTSUPP; + + rcu_read_lock(); + ptr = htab_map_lookup_elem(map, key); + if (ptr) + *value = map->ops->map_fd_sys_lookup_elem(READ_ONCE(*ptr)); + else + ret = -ENOENT; + rcu_read_unlock(); + + return ret; +} + +/* only called from syscall */ +int bpf_fd_htab_map_update_elem(struct bpf_map *map, struct file *map_file, + void *key, void *value, u64 map_flags) +{ + void *ptr; + int ret; + u32 ufd = *(u32 *)value; + + ptr = map->ops->map_fd_get_ptr(map, map_file, ufd); + if (IS_ERR(ptr)) + return PTR_ERR(ptr); + + ret = htab_map_update_elem(map, key, &ptr, map_flags); + if (ret) + map->ops->map_fd_put_ptr(ptr); + + return ret; +} + +static struct bpf_map *htab_of_map_alloc(union bpf_attr *attr) +{ + struct bpf_map *map, *inner_map_meta; + + inner_map_meta = bpf_map_meta_alloc(attr->inner_map_fd); + if (IS_ERR(inner_map_meta)) + return inner_map_meta; + + map = htab_map_alloc(attr); + if (IS_ERR(map)) { + bpf_map_meta_free(inner_map_meta); + return map; + } + + map->inner_map_meta = inner_map_meta; + + return map; +} + +static void *htab_of_map_lookup_elem(struct bpf_map *map, void *key) +{ + struct bpf_map **inner_map = htab_map_lookup_elem(map, key); + + if (!inner_map) + return NULL; + + return READ_ONCE(*inner_map); +} + +static int htab_of_map_gen_lookup(struct bpf_map *map, + struct bpf_insn *insn_buf) +{ + struct bpf_insn *insn = insn_buf; + const int ret = BPF_REG_0; + + BUILD_BUG_ON(!__same_type(&__htab_map_lookup_elem, + (void *(*)(struct bpf_map *map, void *key))NULL)); + *insn++ = BPF_EMIT_CALL(BPF_CAST_CALL(__htab_map_lookup_elem)); + *insn++ = BPF_JMP_IMM(BPF_JEQ, ret, 0, 2); + *insn++ = BPF_ALU64_IMM(BPF_ADD, ret, + offsetof(struct htab_elem, key) + + round_up(map->key_size, 8)); + *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0); + + return insn - insn_buf; +} + +static void htab_of_map_free(struct bpf_map *map) +{ + bpf_map_meta_free(map->inner_map_meta); + fd_htab_map_free(map); +} + +static int htab_of_maps_map_btf_id; +const struct bpf_map_ops htab_of_maps_map_ops = { + .map_alloc_check = fd_htab_map_alloc_check, + .map_alloc = htab_of_map_alloc, + .map_free = htab_of_map_free, + .map_get_next_key = htab_map_get_next_key, + .map_lookup_elem = htab_of_map_lookup_elem, + .map_delete_elem = htab_map_delete_elem, + .map_fd_get_ptr = bpf_map_fd_get_ptr, + .map_fd_put_ptr = bpf_map_fd_put_ptr, + .map_fd_sys_lookup_elem = bpf_map_fd_sys_lookup_elem, + .map_gen_lookup = htab_of_map_gen_lookup, + .map_check_btf = map_check_no_btf, + .map_btf_name = "bpf_htab", + .map_btf_id = &htab_of_maps_map_btf_id, +}; |