diff options
| author | Daniel Borkmann <daniel@iogearbox.net> | 2015-03-13 21:27:16 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-03-15 21:57:25 -0400 |
| commit | 03e69b508b6f7c51743055c9f61d1dfeadf4b635 (patch) | |
| tree | 4c9199cde0fe876871e20352666d40721d4c1d5f /kernel | |
| parent | 12028820423bd7705beb5e09889faab95c545ea1 (diff) | |
ebpf: add prandom helper for packet sampling
This work is similar to commit 4cd3675ebf74 ("filter: added BPF
random opcode") and adds a possibility for packet sampling in eBPF.
Currently, this is only possible in classic BPF and useful to
combine sampling with f.e. packet sockets, possible also with tc.
Example function proto-type looks like:
u32 (*prandom_u32)(void) = (void *)BPF_FUNC_get_prandom_u32;
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/core.c | 2 | ||||
| -rw-r--r-- | kernel/bpf/helpers.c | 12 |
2 files changed, 14 insertions, 0 deletions
diff --git a/kernel/bpf/core.c b/kernel/bpf/core.c index 50603aec766a..c1dbbb5d289b 100644 --- a/kernel/bpf/core.c +++ b/kernel/bpf/core.c | |||
| @@ -661,6 +661,8 @@ const struct bpf_func_proto bpf_map_lookup_elem_proto __weak; | |||
| 661 | const struct bpf_func_proto bpf_map_update_elem_proto __weak; | 661 | const struct bpf_func_proto bpf_map_update_elem_proto __weak; |
| 662 | const struct bpf_func_proto bpf_map_delete_elem_proto __weak; | 662 | const struct bpf_func_proto bpf_map_delete_elem_proto __weak; |
| 663 | 663 | ||
| 664 | const struct bpf_func_proto bpf_get_prandom_u32_proto __weak; | ||
| 665 | |||
| 664 | /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call | 666 | /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call |
| 665 | * skb_copy_bits(), so provide a weak definition of it for NET-less config. | 667 | * skb_copy_bits(), so provide a weak definition of it for NET-less config. |
| 666 | */ | 668 | */ |
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c index a3c7701a8b5e..95eb59a045ea 100644 --- a/kernel/bpf/helpers.c +++ b/kernel/bpf/helpers.c | |||
| @@ -11,6 +11,7 @@ | |||
| 11 | */ | 11 | */ |
| 12 | #include <linux/bpf.h> | 12 | #include <linux/bpf.h> |
| 13 | #include <linux/rcupdate.h> | 13 | #include <linux/rcupdate.h> |
| 14 | #include <linux/random.h> | ||
| 14 | 15 | ||
| 15 | /* If kernel subsystem is allowing eBPF programs to call this function, | 16 | /* If kernel subsystem is allowing eBPF programs to call this function, |
| 16 | * inside its own verifier_ops->get_func_proto() callback it should return | 17 | * inside its own verifier_ops->get_func_proto() callback it should return |
| @@ -87,3 +88,14 @@ const struct bpf_func_proto bpf_map_delete_elem_proto = { | |||
| 87 | .arg1_type = ARG_CONST_MAP_PTR, | 88 | .arg1_type = ARG_CONST_MAP_PTR, |
| 88 | .arg2_type = ARG_PTR_TO_MAP_KEY, | 89 | .arg2_type = ARG_PTR_TO_MAP_KEY, |
| 89 | }; | 90 | }; |
| 91 | |||
| 92 | static u64 bpf_get_prandom_u32(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) | ||
| 93 | { | ||
| 94 | return prandom_u32(); | ||
| 95 | } | ||
| 96 | |||
| 97 | const struct bpf_func_proto bpf_get_prandom_u32_proto = { | ||
| 98 | .func = bpf_get_prandom_u32, | ||
| 99 | .gpl_only = false, | ||
| 100 | .ret_type = RET_INTEGER, | ||
| 101 | }; | ||