bpf: allow eBPF programs to use maps
expose bpf_map_lookup_elem(), bpf_map_update_elem(), bpf_map_delete_elem() map accessors to eBPF programs Signed-off-by: Alexei Starovoitov <ast@plumgrid.com> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
ffb65f27a1
commit
d0003ec01c
|
@ -133,4 +133,9 @@ struct bpf_prog *bpf_prog_get(u32 ufd);
|
||||||
/* verify correctness of eBPF program */
|
/* verify correctness of eBPF program */
|
||||||
int bpf_check(struct bpf_prog *fp, union bpf_attr *attr);
|
int bpf_check(struct bpf_prog *fp, union bpf_attr *attr);
|
||||||
|
|
||||||
|
/* verifier prototypes for helper functions called from eBPF programs */
|
||||||
|
extern struct bpf_func_proto bpf_map_lookup_elem_proto;
|
||||||
|
extern struct bpf_func_proto bpf_map_update_elem_proto;
|
||||||
|
extern struct bpf_func_proto bpf_map_delete_elem_proto;
|
||||||
|
|
||||||
#endif /* _LINUX_BPF_H */
|
#endif /* _LINUX_BPF_H */
|
||||||
|
|
|
@ -158,6 +158,9 @@ union bpf_attr {
|
||||||
*/
|
*/
|
||||||
enum bpf_func_id {
|
enum bpf_func_id {
|
||||||
BPF_FUNC_unspec,
|
BPF_FUNC_unspec,
|
||||||
|
BPF_FUNC_map_lookup_elem, /* void *map_lookup_elem(&map, &key) */
|
||||||
|
BPF_FUNC_map_update_elem, /* int map_update_elem(&map, &key, &value, flags) */
|
||||||
|
BPF_FUNC_map_delete_elem, /* int map_delete_elem(&map, &key) */
|
||||||
__BPF_FUNC_MAX_ID,
|
__BPF_FUNC_MAX_ID,
|
||||||
};
|
};
|
||||||
|
|
||||||
|
|
|
@ -1,5 +1,5 @@
|
||||||
obj-y := core.o
|
obj-y := core.o
|
||||||
obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o hashtab.o arraymap.o
|
obj-$(CONFIG_BPF_SYSCALL) += syscall.o verifier.o hashtab.o arraymap.o helpers.o
|
||||||
ifdef CONFIG_TEST_BPF
|
ifdef CONFIG_TEST_BPF
|
||||||
obj-$(CONFIG_BPF_SYSCALL) += test_stub.o
|
obj-$(CONFIG_BPF_SYSCALL) += test_stub.o
|
||||||
endif
|
endif
|
||||||
|
|
89
kernel/bpf/helpers.c
Normal file
89
kernel/bpf/helpers.c
Normal file
|
@ -0,0 +1,89 @@
|
||||||
|
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
|
||||||
|
*
|
||||||
|
* This program is free software; you can redistribute it and/or
|
||||||
|
* modify it under the terms of version 2 of the GNU General Public
|
||||||
|
* License as published by the Free Software Foundation.
|
||||||
|
*
|
||||||
|
* This program is distributed in the hope that it will be useful, but
|
||||||
|
* WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||||
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||||
|
* General Public License for more details.
|
||||||
|
*/
|
||||||
|
#include <linux/bpf.h>
|
||||||
|
#include <linux/rcupdate.h>
|
||||||
|
|
||||||
|
/* If kernel subsystem is allowing eBPF programs to call this function,
|
||||||
|
* inside its own verifier_ops->get_func_proto() callback it should return
|
||||||
|
* bpf_map_lookup_elem_proto, so that verifier can properly check the arguments
|
||||||
|
*
|
||||||
|
* Different map implementations will rely on rcu in map methods
|
||||||
|
* lookup/update/delete, therefore eBPF programs must run under rcu lock
|
||||||
|
* if program is allowed to access maps, so check rcu_read_lock_held in
|
||||||
|
* all three functions.
|
||||||
|
*/
|
||||||
|
static u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
||||||
|
{
|
||||||
|
/* verifier checked that R1 contains a valid pointer to bpf_map
|
||||||
|
* and R2 points to a program stack and map->key_size bytes were
|
||||||
|
* initialized
|
||||||
|
*/
|
||||||
|
struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
|
||||||
|
void *key = (void *) (unsigned long) r2;
|
||||||
|
void *value;
|
||||||
|
|
||||||
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
||||||
|
|
||||||
|
value = map->ops->map_lookup_elem(map, key);
|
||||||
|
|
||||||
|
/* lookup() returns either pointer to element value or NULL
|
||||||
|
* which is the meaning of PTR_TO_MAP_VALUE_OR_NULL type
|
||||||
|
*/
|
||||||
|
return (unsigned long) value;
|
||||||
|
}
|
||||||
|
|
||||||
|
struct bpf_func_proto bpf_map_lookup_elem_proto = {
|
||||||
|
.func = bpf_map_lookup_elem,
|
||||||
|
.gpl_only = false,
|
||||||
|
.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
|
||||||
|
.arg1_type = ARG_CONST_MAP_PTR,
|
||||||
|
.arg2_type = ARG_PTR_TO_MAP_KEY,
|
||||||
|
};
|
||||||
|
|
||||||
|
static u64 bpf_map_update_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
||||||
|
{
|
||||||
|
struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
|
||||||
|
void *key = (void *) (unsigned long) r2;
|
||||||
|
void *value = (void *) (unsigned long) r3;
|
||||||
|
|
||||||
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
||||||
|
|
||||||
|
return map->ops->map_update_elem(map, key, value, r4);
|
||||||
|
}
|
||||||
|
|
||||||
|
struct bpf_func_proto bpf_map_update_elem_proto = {
|
||||||
|
.func = bpf_map_update_elem,
|
||||||
|
.gpl_only = false,
|
||||||
|
.ret_type = RET_INTEGER,
|
||||||
|
.arg1_type = ARG_CONST_MAP_PTR,
|
||||||
|
.arg2_type = ARG_PTR_TO_MAP_KEY,
|
||||||
|
.arg3_type = ARG_PTR_TO_MAP_VALUE,
|
||||||
|
.arg4_type = ARG_ANYTHING,
|
||||||
|
};
|
||||||
|
|
||||||
|
static u64 bpf_map_delete_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
|
||||||
|
{
|
||||||
|
struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
|
||||||
|
void *key = (void *) (unsigned long) r2;
|
||||||
|
|
||||||
|
WARN_ON_ONCE(!rcu_read_lock_held());
|
||||||
|
|
||||||
|
return map->ops->map_delete_elem(map, key);
|
||||||
|
}
|
||||||
|
|
||||||
|
struct bpf_func_proto bpf_map_delete_elem_proto = {
|
||||||
|
.func = bpf_map_delete_elem,
|
||||||
|
.gpl_only = false,
|
||||||
|
.ret_type = RET_INTEGER,
|
||||||
|
.arg1_type = ARG_CONST_MAP_PTR,
|
||||||
|
.arg2_type = ARG_PTR_TO_MAP_KEY,
|
||||||
|
};
|
Loading…
Reference in New Issue
Block a user