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| author | Alexei Starovoitov <ast@plumgrid.com> | 2015-03-13 11:57:42 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-03-15 22:02:28 -0400 |
| commit | 9bac3d6d548e5cc925570b263f35b70a00a00ffd (patch) | |
| tree | 00ae5c37fb877d7c2b4fdf5ee0b8fe4837b1d476 /kernel/bpf/syscall.c | |
| parent | a498cfe990f569dd3766bfc9bfd2a5ee04468cd2 (diff) | |
| download | op-kernel-dev-9bac3d6d548e5cc925570b263f35b70a00a00ffd.zip op-kernel-dev-9bac3d6d548e5cc925570b263f35b70a00a00ffd.tar.gz | |
bpf: allow extended BPF programs access skb fields
introduce user accessible mirror of in-kernel 'struct sk_buff':
struct __sk_buff {
__u32 len;
__u32 pkt_type;
__u32 mark;
__u32 queue_mapping;
};
bpf programs can do:
int bpf_prog(struct __sk_buff *skb)
{
__u32 var = skb->pkt_type;
which will be compiled to bpf assembler as:
dst_reg = *(u32 *)(src_reg + 4) // 4 == offsetof(struct __sk_buff, pkt_type)
bpf verifier will check validity of access and will convert it to:
dst_reg = *(u8 *)(src_reg + offsetof(struct sk_buff, __pkt_type_offset))
dst_reg &= 7
since skb->pkt_type is a bitfield.
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/bpf/syscall.c')
| -rw-r--r-- | kernel/bpf/syscall.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 669719c..ea75c65 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -519,7 +519,7 @@ static int bpf_prog_load(union bpf_attr *attr) goto free_prog; /* run eBPF verifier */ - err = bpf_check(prog, attr); + err = bpf_check(&prog, attr); if (err < 0) goto free_used_maps; |
