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282 lines
6.6 KiB
282 lines
6.6 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* queue_stack_maps.c: BPF queue and stack maps |
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* |
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* Copyright (c) 2018 Politecnico di Torino |
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*/ |
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#include <linux/bpf.h> |
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#include <linux/list.h> |
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#include <linux/slab.h> |
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#include <linux/capability.h> |
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#include "percpu_freelist.h" |
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#define QUEUE_STACK_CREATE_FLAG_MASK \ |
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(BPF_F_NUMA_NODE | BPF_F_ACCESS_MASK) |
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struct bpf_queue_stack { |
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struct bpf_map map; |
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raw_spinlock_t lock; |
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u32 head, tail; |
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u32 size; /* max_entries + 1 */ |
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char elements[] __aligned(8); |
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}; |
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static struct bpf_queue_stack *bpf_queue_stack(struct bpf_map *map) |
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{ |
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return container_of(map, struct bpf_queue_stack, map); |
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} |
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static bool queue_stack_map_is_empty(struct bpf_queue_stack *qs) |
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{ |
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return qs->head == qs->tail; |
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} |
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static bool queue_stack_map_is_full(struct bpf_queue_stack *qs) |
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{ |
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u32 head = qs->head + 1; |
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if (unlikely(head >= qs->size)) |
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head = 0; |
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return head == qs->tail; |
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} |
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/* Called from syscall */ |
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static int queue_stack_map_alloc_check(union bpf_attr *attr) |
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{ |
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if (!bpf_capable()) |
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return -EPERM; |
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/* check sanity of attributes */ |
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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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attr->map_flags & ~QUEUE_STACK_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 (attr->value_size > KMALLOC_MAX_SIZE) |
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/* if value_size is bigger, the user space won't be able to |
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* access the elements. |
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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 *queue_stack_map_alloc(union bpf_attr *attr) |
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{ |
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int numa_node = bpf_map_attr_numa_node(attr); |
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struct bpf_queue_stack *qs; |
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u64 size, queue_size; |
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size = (u64) attr->max_entries + 1; |
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queue_size = sizeof(*qs) + size * attr->value_size; |
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qs = bpf_map_area_alloc(queue_size, numa_node); |
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if (!qs) |
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return ERR_PTR(-ENOMEM); |
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memset(qs, 0, sizeof(*qs)); |
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bpf_map_init_from_attr(&qs->map, attr); |
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qs->size = size; |
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raw_spin_lock_init(&qs->lock); |
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return &qs->map; |
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} |
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/* Called when map->refcnt goes to zero, either from workqueue or from syscall */ |
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static void queue_stack_map_free(struct bpf_map *map) |
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{ |
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struct bpf_queue_stack *qs = bpf_queue_stack(map); |
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bpf_map_area_free(qs); |
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} |
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static int __queue_map_get(struct bpf_map *map, void *value, bool delete) |
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{ |
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struct bpf_queue_stack *qs = bpf_queue_stack(map); |
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unsigned long flags; |
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int err = 0; |
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void *ptr; |
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raw_spin_lock_irqsave(&qs->lock, flags); |
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if (queue_stack_map_is_empty(qs)) { |
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memset(value, 0, qs->map.value_size); |
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err = -ENOENT; |
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goto out; |
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} |
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ptr = &qs->elements[qs->tail * qs->map.value_size]; |
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memcpy(value, ptr, qs->map.value_size); |
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if (delete) { |
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if (unlikely(++qs->tail >= qs->size)) |
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qs->tail = 0; |
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} |
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out: |
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raw_spin_unlock_irqrestore(&qs->lock, flags); |
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return err; |
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} |
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static int __stack_map_get(struct bpf_map *map, void *value, bool delete) |
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{ |
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struct bpf_queue_stack *qs = bpf_queue_stack(map); |
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unsigned long flags; |
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int err = 0; |
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void *ptr; |
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u32 index; |
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raw_spin_lock_irqsave(&qs->lock, flags); |
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if (queue_stack_map_is_empty(qs)) { |
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memset(value, 0, qs->map.value_size); |
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err = -ENOENT; |
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goto out; |
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} |
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index = qs->head - 1; |
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if (unlikely(index >= qs->size)) |
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index = qs->size - 1; |
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ptr = &qs->elements[index * qs->map.value_size]; |
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memcpy(value, ptr, qs->map.value_size); |
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if (delete) |
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qs->head = index; |
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out: |
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raw_spin_unlock_irqrestore(&qs->lock, flags); |
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return err; |
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} |
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/* Called from syscall or from eBPF program */ |
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static int queue_map_peek_elem(struct bpf_map *map, void *value) |
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{ |
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return __queue_map_get(map, value, false); |
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} |
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/* Called from syscall or from eBPF program */ |
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static int stack_map_peek_elem(struct bpf_map *map, void *value) |
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{ |
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return __stack_map_get(map, value, false); |
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} |
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/* Called from syscall or from eBPF program */ |
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static int queue_map_pop_elem(struct bpf_map *map, void *value) |
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{ |
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return __queue_map_get(map, value, true); |
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} |
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/* Called from syscall or from eBPF program */ |
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static int stack_map_pop_elem(struct bpf_map *map, void *value) |
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{ |
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return __stack_map_get(map, value, true); |
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} |
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/* Called from syscall or from eBPF program */ |
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static int queue_stack_map_push_elem(struct bpf_map *map, void *value, |
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u64 flags) |
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{ |
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struct bpf_queue_stack *qs = bpf_queue_stack(map); |
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unsigned long irq_flags; |
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int err = 0; |
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void *dst; |
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/* BPF_EXIST is used to force making room for a new element in case the |
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* map is full |
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*/ |
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bool replace = (flags & BPF_EXIST); |
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/* Check supported flags for queue and stack maps */ |
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if (flags & BPF_NOEXIST || flags > BPF_EXIST) |
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return -EINVAL; |
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raw_spin_lock_irqsave(&qs->lock, irq_flags); |
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if (queue_stack_map_is_full(qs)) { |
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if (!replace) { |
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err = -E2BIG; |
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goto out; |
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} |
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/* advance tail pointer to overwrite oldest element */ |
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if (unlikely(++qs->tail >= qs->size)) |
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qs->tail = 0; |
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} |
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dst = &qs->elements[qs->head * qs->map.value_size]; |
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memcpy(dst, value, qs->map.value_size); |
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if (unlikely(++qs->head >= qs->size)) |
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qs->head = 0; |
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out: |
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raw_spin_unlock_irqrestore(&qs->lock, irq_flags); |
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return err; |
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} |
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/* Called from syscall or from eBPF program */ |
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static void *queue_stack_map_lookup_elem(struct bpf_map *map, void *key) |
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{ |
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return NULL; |
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} |
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/* Called from syscall or from eBPF program */ |
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static int queue_stack_map_update_elem(struct bpf_map *map, void *key, |
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void *value, u64 flags) |
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{ |
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return -EINVAL; |
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} |
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/* Called from syscall or from eBPF program */ |
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static int queue_stack_map_delete_elem(struct bpf_map *map, void *key) |
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{ |
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return -EINVAL; |
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} |
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/* Called from syscall */ |
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static int queue_stack_map_get_next_key(struct bpf_map *map, void *key, |
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void *next_key) |
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{ |
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return -EINVAL; |
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} |
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static int queue_map_btf_id; |
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const struct bpf_map_ops queue_map_ops = { |
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.map_meta_equal = bpf_map_meta_equal, |
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.map_alloc_check = queue_stack_map_alloc_check, |
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.map_alloc = queue_stack_map_alloc, |
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.map_free = queue_stack_map_free, |
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.map_lookup_elem = queue_stack_map_lookup_elem, |
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.map_update_elem = queue_stack_map_update_elem, |
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.map_delete_elem = queue_stack_map_delete_elem, |
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.map_push_elem = queue_stack_map_push_elem, |
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.map_pop_elem = queue_map_pop_elem, |
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.map_peek_elem = queue_map_peek_elem, |
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.map_get_next_key = queue_stack_map_get_next_key, |
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.map_btf_name = "bpf_queue_stack", |
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.map_btf_id = &queue_map_btf_id, |
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}; |
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static int stack_map_btf_id; |
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const struct bpf_map_ops stack_map_ops = { |
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.map_meta_equal = bpf_map_meta_equal, |
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.map_alloc_check = queue_stack_map_alloc_check, |
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.map_alloc = queue_stack_map_alloc, |
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.map_free = queue_stack_map_free, |
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.map_lookup_elem = queue_stack_map_lookup_elem, |
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.map_update_elem = queue_stack_map_update_elem, |
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.map_delete_elem = queue_stack_map_delete_elem, |
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.map_push_elem = queue_stack_map_push_elem, |
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.map_pop_elem = stack_map_pop_elem, |
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.map_peek_elem = stack_map_peek_elem, |
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.map_get_next_key = queue_stack_map_get_next_key, |
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.map_btf_name = "bpf_queue_stack", |
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.map_btf_id = &stack_map_btf_id, |
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};
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