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![Alexei Starovoitov](/assets/img/avatar_default.png)
Implement permissions as stated in uapi/linux/capability.h In order to do that the verifier allow_ptr_leaks flag is split into four flags and they are set as: env->allow_ptr_leaks = bpf_allow_ptr_leaks(); env->bypass_spec_v1 = bpf_bypass_spec_v1(); env->bypass_spec_v4 = bpf_bypass_spec_v4(); env->bpf_capable = bpf_capable(); The first three currently equivalent to perfmon_capable(), since leaking kernel pointers and reading kernel memory via side channel attacks is roughly equivalent to reading kernel memory with cap_perfmon. 'bpf_capable' enables bounded loops, precision tracking, bpf to bpf calls and other verifier features. 'allow_ptr_leaks' enable ptr leaks, ptr conversions, subtraction of pointers. 'bypass_spec_v1' disables speculative analysis in the verifier, run time mitigations in bpf array, and enables indirect variable access in bpf programs. 'bypass_spec_v4' disables emission of sanitation code by the verifier. That means that the networking BPF program loaded with CAP_BPF + CAP_NET_ADMIN will have speculative checks done by the verifier and other spectre mitigation applied. Such networking BPF program will not be able to leak kernel pointers and will not be able to access arbitrary kernel memory. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20200513230355.7858-3-alexei.starovoitov@gmail.com
1902 lines
49 KiB
C
1902 lines
49 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
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* Copyright (c) 2016 Facebook
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*/
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#include <linux/bpf.h>
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#include <linux/btf.h>
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#include <linux/jhash.h>
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#include <linux/filter.h>
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#include <linux/rculist_nulls.h>
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#include <linux/random.h>
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#include <uapi/linux/btf.h>
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#include "percpu_freelist.h"
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#include "bpf_lru_list.h"
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#include "map_in_map.h"
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#define HTAB_CREATE_FLAG_MASK \
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(BPF_F_NO_PREALLOC | BPF_F_NO_COMMON_LRU | BPF_F_NUMA_NODE | \
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BPF_F_ACCESS_MASK | BPF_F_ZERO_SEED)
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#define BATCH_OPS(_name) \
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.map_lookup_batch = \
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_name##_map_lookup_batch, \
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.map_lookup_and_delete_batch = \
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_name##_map_lookup_and_delete_batch, \
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.map_update_batch = \
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generic_map_update_batch, \
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.map_delete_batch = \
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generic_map_delete_batch
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/*
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* The bucket lock has two protection scopes:
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*
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* 1) Serializing concurrent operations from BPF programs on differrent
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* CPUs
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*
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* 2) Serializing concurrent operations from BPF programs and sys_bpf()
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*
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* BPF programs can execute in any context including perf, kprobes and
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* tracing. As there are almost no limits where perf, kprobes and tracing
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* can be invoked from the lock operations need to be protected against
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* deadlocks. Deadlocks can be caused by recursion and by an invocation in
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* the lock held section when functions which acquire this lock are invoked
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* from sys_bpf(). BPF recursion is prevented by incrementing the per CPU
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* variable bpf_prog_active, which prevents BPF programs attached to perf
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* events, kprobes and tracing to be invoked before the prior invocation
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* from one of these contexts completed. sys_bpf() uses the same mechanism
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* by pinning the task to the current CPU and incrementing the recursion
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* protection accross the map operation.
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*
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* This has subtle implications on PREEMPT_RT. PREEMPT_RT forbids certain
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* operations like memory allocations (even with GFP_ATOMIC) from atomic
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* contexts. This is required because even with GFP_ATOMIC the memory
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* allocator calls into code pathes which acquire locks with long held lock
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* sections. To ensure the deterministic behaviour these locks are regular
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* spinlocks, which are converted to 'sleepable' spinlocks on RT. The only
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* true atomic contexts on an RT kernel are the low level hardware
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* handling, scheduling, low level interrupt handling, NMIs etc. None of
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* these contexts should ever do memory allocations.
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*
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* As regular device interrupt handlers and soft interrupts are forced into
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* thread context, the existing code which does
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* spin_lock*(); alloc(GPF_ATOMIC); spin_unlock*();
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* just works.
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*
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* In theory the BPF locks could be converted to regular spinlocks as well,
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* but the bucket locks and percpu_freelist locks can be taken from
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* arbitrary contexts (perf, kprobes, tracepoints) which are required to be
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* atomic contexts even on RT. These mechanisms require preallocated maps,
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* so there is no need to invoke memory allocations within the lock held
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* sections.
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*
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* BPF maps which need dynamic allocation are only used from (forced)
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* thread context on RT and can therefore use regular spinlocks which in
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* turn allows to invoke memory allocations from the lock held section.
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*
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* On a non RT kernel this distinction is neither possible nor required.
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* spinlock maps to raw_spinlock and the extra code is optimized out by the
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* compiler.
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*/
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struct bucket {
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struct hlist_nulls_head head;
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union {
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raw_spinlock_t raw_lock;
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spinlock_t lock;
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};
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};
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struct bpf_htab {
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struct bpf_map map;
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struct bucket *buckets;
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void *elems;
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union {
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struct pcpu_freelist freelist;
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struct bpf_lru lru;
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};
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struct htab_elem *__percpu *extra_elems;
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atomic_t count; /* number of elements in this hashtable */
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u32 n_buckets; /* number of hash buckets */
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u32 elem_size; /* size of each element in bytes */
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u32 hashrnd;
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};
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/* each htab element is struct htab_elem + key + value */
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struct htab_elem {
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union {
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struct hlist_nulls_node hash_node;
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struct {
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void *padding;
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union {
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struct bpf_htab *htab;
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struct pcpu_freelist_node fnode;
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struct htab_elem *batch_flink;
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};
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};
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};
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union {
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struct rcu_head rcu;
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struct bpf_lru_node lru_node;
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};
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u32 hash;
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char key[] __aligned(8);
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};
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static inline bool htab_is_prealloc(const struct bpf_htab *htab)
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{
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return !(htab->map.map_flags & BPF_F_NO_PREALLOC);
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}
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static inline bool htab_use_raw_lock(const struct bpf_htab *htab)
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{
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return (!IS_ENABLED(CONFIG_PREEMPT_RT) || htab_is_prealloc(htab));
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}
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static void htab_init_buckets(struct bpf_htab *htab)
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{
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unsigned i;
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for (i = 0; i < htab->n_buckets; i++) {
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INIT_HLIST_NULLS_HEAD(&htab->buckets[i].head, i);
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if (htab_use_raw_lock(htab))
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raw_spin_lock_init(&htab->buckets[i].raw_lock);
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else
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spin_lock_init(&htab->buckets[i].lock);
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}
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}
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static inline unsigned long htab_lock_bucket(const struct bpf_htab *htab,
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struct bucket *b)
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{
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unsigned long flags;
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if (htab_use_raw_lock(htab))
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raw_spin_lock_irqsave(&b->raw_lock, flags);
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else
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spin_lock_irqsave(&b->lock, flags);
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return flags;
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}
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static inline void htab_unlock_bucket(const struct bpf_htab *htab,
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struct bucket *b,
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unsigned long flags)
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{
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if (htab_use_raw_lock(htab))
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raw_spin_unlock_irqrestore(&b->raw_lock, flags);
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else
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spin_unlock_irqrestore(&b->lock, flags);
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}
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static bool htab_lru_map_delete_node(void *arg, struct bpf_lru_node *node);
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static bool htab_is_lru(const struct bpf_htab *htab)
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{
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return htab->map.map_type == BPF_MAP_TYPE_LRU_HASH ||
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htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
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}
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static bool htab_is_percpu(const struct bpf_htab *htab)
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{
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return htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH ||
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htab->map.map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH;
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}
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static inline void htab_elem_set_ptr(struct htab_elem *l, u32 key_size,
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void __percpu *pptr)
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{
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*(void __percpu **)(l->key + key_size) = pptr;
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}
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static inline void __percpu *htab_elem_get_ptr(struct htab_elem *l, u32 key_size)
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{
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return *(void __percpu **)(l->key + key_size);
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}
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static void *fd_htab_map_get_ptr(const struct bpf_map *map, struct htab_elem *l)
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{
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return *(void **)(l->key + roundup(map->key_size, 8));
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}
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static struct htab_elem *get_htab_elem(struct bpf_htab *htab, int i)
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{
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return (struct htab_elem *) (htab->elems + i * htab->elem_size);
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}
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static void htab_free_elems(struct bpf_htab *htab)
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{
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int i;
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if (!htab_is_percpu(htab))
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goto free_elems;
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for (i = 0; i < htab->map.max_entries; i++) {
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void __percpu *pptr;
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pptr = htab_elem_get_ptr(get_htab_elem(htab, i),
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htab->map.key_size);
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free_percpu(pptr);
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cond_resched();
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}
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free_elems:
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bpf_map_area_free(htab->elems);
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}
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/* The LRU list has a lock (lru_lock). Each htab bucket has a lock
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* (bucket_lock). If both locks need to be acquired together, the lock
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* order is always lru_lock -> bucket_lock and this only happens in
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* bpf_lru_list.c logic. For example, certain code path of
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* bpf_lru_pop_free(), which is called by function prealloc_lru_pop(),
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* will acquire lru_lock first followed by acquiring bucket_lock.
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*
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* In hashtab.c, to avoid deadlock, lock acquisition of
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* bucket_lock followed by lru_lock is not allowed. In such cases,
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* bucket_lock needs to be released first before acquiring lru_lock.
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*/
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static struct htab_elem *prealloc_lru_pop(struct bpf_htab *htab, void *key,
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u32 hash)
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{
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struct bpf_lru_node *node = bpf_lru_pop_free(&htab->lru, hash);
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struct htab_elem *l;
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if (node) {
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l = container_of(node, struct htab_elem, lru_node);
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memcpy(l->key, key, htab->map.key_size);
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return l;
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}
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return NULL;
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}
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static int prealloc_init(struct bpf_htab *htab)
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{
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u32 num_entries = htab->map.max_entries;
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int err = -ENOMEM, i;
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if (!htab_is_percpu(htab) && !htab_is_lru(htab))
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num_entries += num_possible_cpus();
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htab->elems = bpf_map_area_alloc(htab->elem_size * num_entries,
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htab->map.numa_node);
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if (!htab->elems)
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return -ENOMEM;
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if (!htab_is_percpu(htab))
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goto skip_percpu_elems;
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for (i = 0; i < num_entries; i++) {
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u32 size = round_up(htab->map.value_size, 8);
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void __percpu *pptr;
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pptr = __alloc_percpu_gfp(size, 8, GFP_USER | __GFP_NOWARN);
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if (!pptr)
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goto free_elems;
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htab_elem_set_ptr(get_htab_elem(htab, i), htab->map.key_size,
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pptr);
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cond_resched();
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}
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skip_percpu_elems:
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if (htab_is_lru(htab))
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err = bpf_lru_init(&htab->lru,
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htab->map.map_flags & BPF_F_NO_COMMON_LRU,
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offsetof(struct htab_elem, hash) -
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offsetof(struct htab_elem, lru_node),
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htab_lru_map_delete_node,
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htab);
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else
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err = pcpu_freelist_init(&htab->freelist);
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if (err)
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goto free_elems;
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if (htab_is_lru(htab))
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bpf_lru_populate(&htab->lru, htab->elems,
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offsetof(struct htab_elem, lru_node),
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htab->elem_size, num_entries);
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else
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pcpu_freelist_populate(&htab->freelist,
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htab->elems + offsetof(struct htab_elem, fnode),
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htab->elem_size, num_entries);
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return 0;
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free_elems:
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htab_free_elems(htab);
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return err;
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}
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static void prealloc_destroy(struct bpf_htab *htab)
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{
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htab_free_elems(htab);
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if (htab_is_lru(htab))
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bpf_lru_destroy(&htab->lru);
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else
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pcpu_freelist_destroy(&htab->freelist);
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}
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static int alloc_extra_elems(struct bpf_htab *htab)
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{
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struct htab_elem *__percpu *pptr, *l_new;
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struct pcpu_freelist_node *l;
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int cpu;
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pptr = __alloc_percpu_gfp(sizeof(struct htab_elem *), 8,
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GFP_USER | __GFP_NOWARN);
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if (!pptr)
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return -ENOMEM;
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for_each_possible_cpu(cpu) {
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l = pcpu_freelist_pop(&htab->freelist);
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/* pop will succeed, since prealloc_init()
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* preallocated extra num_possible_cpus elements
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*/
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l_new = container_of(l, struct htab_elem, fnode);
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*per_cpu_ptr(pptr, cpu) = l_new;
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}
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htab->extra_elems = pptr;
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return 0;
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}
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/* Called from syscall */
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static int htab_map_alloc_check(union bpf_attr *attr)
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{
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bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
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attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
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bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
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attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
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/* percpu_lru means each cpu has its own LRU list.
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* it is different from BPF_MAP_TYPE_PERCPU_HASH where
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* the map's value itself is percpu. percpu_lru has
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* nothing to do with the map's value.
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*/
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bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
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bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
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bool zero_seed = (attr->map_flags & BPF_F_ZERO_SEED);
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int numa_node = bpf_map_attr_numa_node(attr);
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BUILD_BUG_ON(offsetof(struct htab_elem, htab) !=
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offsetof(struct htab_elem, hash_node.pprev));
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BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) !=
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offsetof(struct htab_elem, hash_node.pprev));
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if (lru && !bpf_capable())
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/* LRU implementation is much complicated than other
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* maps. Hence, limit to CAP_BPF.
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*/
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return -EPERM;
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if (zero_seed && !capable(CAP_SYS_ADMIN))
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/* Guard against local DoS, and discourage production use. */
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return -EPERM;
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if (attr->map_flags & ~HTAB_CREATE_FLAG_MASK ||
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!bpf_map_flags_access_ok(attr->map_flags))
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return -EINVAL;
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if (!lru && percpu_lru)
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return -EINVAL;
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if (lru && !prealloc)
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return -ENOTSUPP;
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if (numa_node != NUMA_NO_NODE && (percpu || percpu_lru))
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return -EINVAL;
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/* check sanity of attributes.
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* value_size == 0 may be allowed in the future to use map as a set
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*/
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if (attr->max_entries == 0 || attr->key_size == 0 ||
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attr->value_size == 0)
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return -EINVAL;
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if (attr->key_size > MAX_BPF_STACK)
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/* eBPF programs initialize keys on stack, so they cannot be
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* larger than max stack size
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*/
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return -E2BIG;
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if (attr->value_size >= KMALLOC_MAX_SIZE -
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MAX_BPF_STACK - sizeof(struct htab_elem))
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/* if value_size is bigger, the user space won't be able to
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* access the elements via bpf syscall. This check also makes
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* sure that the elem_size doesn't overflow and it's
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* kmalloc-able later in htab_map_update_elem()
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*/
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return -E2BIG;
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return 0;
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}
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static struct bpf_map *htab_map_alloc(union bpf_attr *attr)
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{
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bool percpu = (attr->map_type == BPF_MAP_TYPE_PERCPU_HASH ||
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attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
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bool lru = (attr->map_type == BPF_MAP_TYPE_LRU_HASH ||
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attr->map_type == BPF_MAP_TYPE_LRU_PERCPU_HASH);
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/* percpu_lru means each cpu has its own LRU list.
|
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* it is different from BPF_MAP_TYPE_PERCPU_HASH where
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* the map's value itself is percpu. percpu_lru has
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* nothing to do with the map's value.
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*/
|
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bool percpu_lru = (attr->map_flags & BPF_F_NO_COMMON_LRU);
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bool prealloc = !(attr->map_flags & BPF_F_NO_PREALLOC);
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struct bpf_htab *htab;
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u64 cost;
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int err;
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htab = kzalloc(sizeof(*htab), GFP_USER);
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if (!htab)
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return ERR_PTR(-ENOMEM);
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|
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bpf_map_init_from_attr(&htab->map, attr);
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|
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if (percpu_lru) {
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/* ensure each CPU's lru list has >=1 elements.
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* since we are at it, make each lru list has the same
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* number of elements.
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*/
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htab->map.max_entries = roundup(attr->max_entries,
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num_possible_cpus());
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if (htab->map.max_entries < attr->max_entries)
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htab->map.max_entries = rounddown(attr->max_entries,
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num_possible_cpus());
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}
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|
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/* hash table size must be power of 2 */
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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;
|
|
|
|
/* 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, 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 u32 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 u32 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 free_htab_elem(struct bpf_htab *htab, struct htab_elem *l)
|
|
{
|
|
struct bpf_map *map = &htab->map;
|
|
|
|
if (map->ops->map_fd_put_ptr) {
|
|
void *ptr = fd_htab_map_get_ptr(map, l);
|
|
|
|
map->ops->map_fd_put_ptr(ptr);
|
|
}
|
|
|
|
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 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;
|
|
*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_copy_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());
|
|
|
|
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());
|
|
|
|
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_copy_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());
|
|
|
|
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());
|
|
|
|
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);
|
|
|
|
/* 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 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(key_size * bucket_size, GFP_USER | __GFP_NOWARN);
|
|
values = kvmalloc(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);
|
|
}
|
|
|
|
const struct bpf_map_ops htab_map_ops = {
|
|
.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),
|
|
};
|
|
|
|
const struct bpf_map_ops htab_lru_map_ops = {
|
|
.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),
|
|
};
|
|
|
|
/* 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();
|
|
}
|
|
|
|
const struct bpf_map_ops htab_percpu_map_ops = {
|
|
.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),
|
|
};
|
|
|
|
const struct bpf_map_ops htab_lru_percpu_map_ops = {
|
|
.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),
|
|
};
|
|
|
|
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 u32 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);
|
|
}
|
|
|
|
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,
|
|
};
|